{"title":"Cylinder Head Packages","description":"\u003cp\u003eOur 5-axis Rottler CNC and Newen Contour seat and guide machines are the most advanced on the market today. This allows us to produce ported heads of exceptional quality and performance.  How do we know? Because we use them ourselves!\u003c\/p\u003e\n\u003cp\u003eThe LS heads normally in stock are GM LS3 (seasoned), AFR LS, All Pro LS, Dart LS and Dart BBC.  The aftermarket heads come in as raw porter castings into which we machine our desired combustion chamber and port. The LS heads can be finsiged to either LS3 or LS7 ports.  We have a wide array of valve and spring types to choose from.  Call us at 815-725-2727 to get the perfect set of heads for your needs.\u003c\/p\u003e","products":[{"product_id":"all-pro-cylinder-heads-hydraulic-cam-manley-stainless-intake-extreme-duty-inconel-exhaust","title":"All Pro Cylinder Heads, Assembled, for Hydraulic Cams, LS3 or LS7 Ports","description":"\u003cdiv class=\"descWrapper\"\u003e\n\u003cdiv\u003eAt Borowski Race Engines, we use ALL PRO heads on most of our big power LS engine builds with hydraulic roller cams. Here are some reasons why:\u003cbr\u003e\u003cbr\u003e- Great air flow (380 cfm at 0.70\" lift) as shown in photoset charts\u003c\/div\u003e\n\u003cdiv\u003e- 100% virgin Alcoa aluminum ingot with no remelt\u003cbr\u003e- Heads have been fully HIP treated (hot isostatic pressing) for greater strength and dimensional stability\u003cbr\u003e- Up to 1 inch deck thickness, 0.75 inch minimum\u003cbr\u003e- Enhanced six-bolt design\u003c\/div\u003e\n\u003cdiv\u003e- Billet rocker rails instead of bosses which we have found to be prone to cracking on other heads\u003c\/div\u003e\n\u003cdiv\u003e- Suitable for either traditional or shaft rockers\u003c\/div\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv\u003e\u003cimg alt=\"\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0248\/9809\/files\/IMG_3158.jpg?v=1722636933\" width=\"528\" height=\"396\"\u003e\u003c\/div\u003e\n\u003cdiv\u003eWe buy these heads as 12-degree, LS7 design porter castings. We are able to impart either LS3 or LS7 shape ports when we machine them on our 5-axis CNC.  \u003cspan\u003eOur Newen CNC seat \u0026amp; guide machine does the valve job and bowl blending in one operation. Watch the videos below to see the 5-axis and Newen at work.\u003c\/span\u003e\n\u003c\/div\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv\u003e\u003ciframe title=\"YouTube video player\" src=\"https:\/\/www.youtube.com\/embed\/FX7HCBxF88g?si=TXRjD3JYcDlFYfbs\" height=\"315\" width=\"560\"\u003e\u003c\/iframe\u003e\u003c\/div\u003e\n\u003cdiv\u003e\n\u003cspan\u003e\u003c\/span\u003e\u003cbr\u003e\n\u003c\/div\u003e\n\u003cdiv\u003e\u003cspan\u003e\u003ciframe title=\"YouTube video player\" src=\"https:\/\/www.youtube.com\/embed\/Vi_TFjKdPn8?si=us6M8LJ_hAIW3H36\" height=\"315\" width=\"560\"\u003e\u003c\/iframe\u003e\u003c\/span\u003e\u003c\/div\u003e\n\u003cdiv\u003e\n\u003cspan\u003e\u003c\/span\u003e\u003cbr\u003e\n\u003c\/div\u003e\n\u003cdiv\u003e\n\u003cspan\u003eStandard hardware:\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e- Manley Severe Duty Stainless Steel 2.200\" Intake Valves\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e- Manley Extreme Duty Inconel 1.615\" Exhaust Valves\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e- Manley NexTek Valve Springs\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e- Manley Machined Bead 7 Degree Valve Locks\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e- Manley Retainers and Locators\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e- Billet Aluminum Rocker Arm Stand with ARP Bolts\u003c\/span\u003e\u003cbr\u003e\u003cbr\u003e\u003cspan\u003eNot exactly what you need? Looking for really a special spring package, big boost, solid heads, mechanical cam, titanium valves, etc.? Give us a call at 815-725-2727. We can machine and assemble whatever you need from either these or other available All Pro castings.\u003c\/span\u003e\n\u003c\/div\u003e\n\u003cdiv\u003e\n\u003cbr\u003eBe sure to watch the videos below to hear about the head design, manufacture and HIP treatment directly from Bob Williams, owner of All Pro Cylinder Heads.  You also should hear what the owner of Cutaway Racing has to say about their performance as he has used plenty of them.\u003cbr\u003e\u003cbr\u003ePriced per pair.\u003c\/div\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv\u003e\u003ciframe width=\"560\" height=\"315\" src=\"https:\/\/www.youtube.com\/embed\/NFyY2e6Plb8\" title=\"YouTube video player\"\u003e\u003c\/iframe\u003e\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv style=\"padding: 177.78% 0 0 0; position: relative;\"\u003e\u003ciframe title=\"HIPS Treatment\" style=\"position: absolute; top: 0; left: 0; width: 100%; height: 100%;\" src=\"https:\/\/player.vimeo.com\/video\/974298254?badge=0\u0026amp;autopause=0\u0026amp;player_id=0\u0026amp;app_id=58479\"\u003e\u003c\/iframe\u003e\u003c\/div\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cdiv style=\"padding: 177.78% 0 0 0; position: relative;\"\u003e\u003ciframe title=\"Cutaway Racing's John McGhee on BRE Hydraulic Roller Long Blocks\" style=\"position: absolute; top: 0; left: 0; width: 100%; height: 100%;\" src=\"https:\/\/player.vimeo.com\/video\/993713002?badge=0\u0026amp;autopause=0\u0026amp;player_id=0\u0026amp;app_id=58479\"\u003e\u003c\/iframe\u003e\u003c\/div\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003ePayment Methods Accepted: cash, ACH, wire transfer, credit card subject to approval and fees\u003c\/p\u003e","brand":"All Pro Cylinder Heads","offers":[{"title":"LS3","offer_id":43952947364052,"sku":"BRE043551","price":5175.0,"currency_code":"USD","in_stock":true},{"title":"LS7","offer_id":43952947396820,"sku":"BRE043553","price":5175.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0248\/9809\/files\/IMG_3103sq.jpg?v=1722547762"},{"product_id":"copy-of-all-pro-cylinder-heads-mechanical-cam-up-to-670-lift-titanium-intake-inconel-exhaust","title":"All Pro Cylinder Heads - Mechanical Cam, Titanium Intake, Inconel Exhaust","description":"\u003cp\u003eThis is the cylinder head we use for all of our big boost engines other than the\u003ca rel=\"noopener\" title=\"All Pro solid LS7 heads\" href=\"https:\/\/borowskirace.com\/products\/all-pro-cylinder-solid-ls-heads-mechanical-cam-ferrea-titanium-valves?variant=45677208273108\" target=\"_blank\"\u003e All Pro solid heads\u003c\/a\u003e used with billet blocks and no water. They have g\u003cspan style=\"font-size: 0.875rem;\"\u003ereat airflow (see airflow chart in photoset) and \u003c\/span\u003eare amazingly strong and here's why:  \u003cbr\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan style=\"font-size: 0.875rem;\"\u003e100% virgin Alcoa aerospace-grade aluminum ingot with no remelt\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eHeads have been HIP treated (hot isostatic pressing) for greater strength and dimensional stability (see video below for more details on HIP treatment)\u003c\/span\u003e\u003c\/li\u003e\n\u003cli style=\"text-align: left;\"\u003e\n\u003cspan\u003eUp to 1 inch deck thickness, 0.75 inch minimum\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003eEnhanced six-bolt design\u003c\/span\u003e\u003cbr\u003e\u003cbr\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cspan\u003e\u003ciframe width=\"560\" height=\"315\" src=\"https:\/\/www.youtube.com\/embed\/FX7HCBxF88g\" title=\"YouTube video player\"\u003e\u003c\/iframe\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eOur custom CNC work brings them to their maximum performance. \u003c\/span\u003eThese All Pro LS7 cylinder heads come with:\u003cbr\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan\u003eShaft mount rocker provisions,\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eBorowski CNC porting for big boost applications,\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eNewen CNC valve job,\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eCustom Titanium Intake 2.200\" Valves\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eManley Extreme Duty Inconel 1.615\" exhaust valves,\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eManley NexTek Valve Springs (up to .900 lift),\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eManley Machined 10 Degree Bead Locks and Retainers\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cspan\u003eWe buy these heads as porter castings and are therefore able to impart our own designs when we port them on our 5-axis CNC. Our Newen CNC seat \u0026amp; guide machine does the valve job and bowl blending in one operation. The port volumes after machining are 290cc and 108cc for Intake and Exhaust ports respectively.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eCall us at 815-725-2727 with any questions.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003ePriced per pair.\u003c\/span\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003eLearn more about All Pro heads from Bob Williams, owner of All Pro Cylinder Heads \u003c\/p\u003e\n\u003cp\u003e\u003ciframe title=\"YouTube video player\" src=\"https:\/\/www.youtube.com\/embed\/NFyY2e6Plb8\" height=\"315\" width=\"560\"\u003e\u003c\/iframe\u003e \u003c\/p\u003e\n\u003cp\u003eNewen CNC Seat \u0026amp; Guide Machine\u003c\/p\u003e\n\u003cp\u003e\u003ciframe title=\"YouTube video player\" src=\"https:\/\/www.youtube.com\/embed\/Vi_TFjKdPn8?si=vB5vAiYZYGla1Go8\" height=\"315\" width=\"560\"\u003e\u003c\/iframe\u003e\u003c\/p\u003e\n\u003cp\u003eHere's a set of the dry version of these heads at work on a ProSpeed's dyno.\u003c\/p\u003e\n\u003cp\u003e\u003ciframe title=\"YouTube video player\" src=\"https:\/\/www.youtube.com\/embed\/ZPMAXjOlY1A\" height=\"315\" width=\"560\"\u003e\u003c\/iframe\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003eWhy HIP treatment is important\u003c\/p\u003e\n\u003cp\u003e\u003ciframe height=\"360\" width=\"640\" src=\"https:\/\/player.vimeo.com\/video\/974298254?h=f1f7aedac4\" title=\"vimeo-player\"\u003e\u003c\/iframe\u003e\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e","brand":"All Pro Cylinder Heads","offers":[{"title":"Default Title","offer_id":4734687182875,"sku":"BRE043574","price":7395.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0248\/9809\/files\/IMG_2972_sq.jpg?v=1740614129"},{"product_id":"gm-ls3-heads-823-castings-fully-cncd","title":"CNC Ported Stage III GM LS3 Cylinder Heads","description":"\u003csection class=\"adDescription\"\u003e\n\u003cdiv class=\"descWrapper\"\u003e\n\u003cdiv itemprop=\"description\"\u003ePRICES ARE PER PAIR - NO CORE CHARGE\u003c\/div\u003e\n\u003cdiv itemprop=\"description\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv itemprop=\"description\"\u003eThese seasoned GM LS3 heads have finally been given a chance to breathe after a full treatment on our state-of-the-art CNC equipment. That includes porting on our 5-axis, a CNC valve job on our Newen Contour and getting milled to perfect flatness on our Berco (see videos down below).\u003cbr\u003e\u003cbr\u003eThe port work brings the intake runner volume from 257 to 284cc. The exhaust is increased from 87 to 99cc. Take a close look at the spin video and photos showing unsurpassed quality of the machining work.\u003cspan\u003e \u003c\/span\u003e\n\u003c\/div\u003e\n\u003cdiv itemprop=\"description\"\u003e\n\u003cspan\u003e\u003c\/span\u003e\u003cbr\u003e\n\u003c\/div\u003e\n\u003cdiv itemprop=\"description\"\u003e\n\u003ciframe src=\"\/\/spins0.arqspin.com\/iframe.html?spin=3emdukd4g696k\u0026amp;is=0.16\" width=\"512\" height=\"512\" scrolling=\"no\" frameborder=\"0\"\u003e\u003c\/iframe\u003e\u003cbr\u003e\n\u003c\/div\u003e\n\u003cdiv itemprop=\"description\"\u003eAs seen in the chart below, our CNC porting has the most pronounced effect on exhaust side airflow.  \u003c\/div\u003e\n\u003cdiv itemprop=\"description\"\u003e\u003cimg alt=\"\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0248\/9809\/files\/GM_LS3_Flow_Data.jpg?v=1723244236\"\u003e\u003c\/div\u003e\n\u003cdiv itemprop=\"description\"\u003e\u003cspan\u003eWe assemble these heads using GM valves, and beehive springs .625\" Max Lift, Coil Bind @ 1.060\".  Other valve and spring packages are available.\u003c\/span\u003e\u003c\/div\u003e\n\u003cdiv itemprop=\"description\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv itemprop=\"description\"\u003eUnlike pure head porters, we build engines. While flow numbers are useful information, \u003c\/div\u003e\n\u003cdiv itemprop=\"description\"\u003ewe really like to see how they do on our dyno. Better yet, we want to see how they do on the track. Furthermore, we intentionally sacrifice air flow to preserve the valve guide. Who needs a head that will eventually grenade an engine due to its missing half the valve guide?\u003c\/div\u003e\n\u003cdiv itemprop=\"description\"\u003e\n\u003cbr\u003eAnd yes, we eat our own cooking. A set of these heads were on the GMC Canyon that our General Manager ran for Drag Week 2018. His naturally-aspirated, pump-gas LS3 produced 766 hp on our dyno.\u003c\/div\u003e\n\u003cdiv itemprop=\"description\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv itemprop=\"description\"\u003e\u003ciframe width=\"560\" height=\"315\" src=\"https:\/\/www.youtube.com\/embed\/jegUzKb1_sM\" title=\"YouTube video player\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture\" allowfullscreen=\"\"\u003e\u003c\/iframe\u003e\u003c\/div\u003e\n\u003cdiv itemprop=\"description\"\u003e\n\u003cbr\u003eCall us at 815-725-2727 to order a set for your car now either bare or assembled to suit.  By the way, these heads now come with our engraved logo as standard.  See the videos below to see how we do our machining.\u003c\/div\u003e\n\u003cdiv itemprop=\"description\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv itemprop=\"description\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv itemprop=\"description\"\u003e\u003ciframe title=\"YouTube video player\" src=\"https:\/\/www.youtube.com\/embed\/tswpi1ULaOY?si=8FEE-7FGV5P1AF7y\" height=\"315\" width=\"560\" allowfullscreen=\"\" referrerpolicy=\"strict-origin-when-cross-origin\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" frameborder=\"0\"\u003e\u003c\/iframe\u003e\u003c\/div\u003e\n\u003cdiv itemprop=\"description\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv itemprop=\"description\"\u003e\u003ciframe title=\"YouTube video player\" src=\"https:\/\/www.youtube.com\/embed\/Vi_TFjKdPn8?si=Xu1PNMCePiVbFrl9\" height=\"315\" width=\"560\" allowfullscreen=\"\" referrerpolicy=\"strict-origin-when-cross-origin\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" frameborder=\"0\"\u003e\u003c\/iframe\u003e\u003c\/div\u003e\n\u003cdiv style=\"text-align: center;\" itemprop=\"description\"\u003e\u003ciframe title=\"YouTube video player\" src=\"https:\/\/www.youtube.com\/embed\/zM_MiSF_69U?si=j-t3QnUG62RpQOld\" height=\"315\" width=\"560\" allowfullscreen=\"\" referrerpolicy=\"strict-origin-when-cross-origin\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" frameborder=\"0\"\u003e\u003c\/iframe\u003e\u003c\/div\u003e\n\u003cdiv itemprop=\"description\"\u003e\n\u003cdiv itemprop=\"description\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv itemprop=\"description\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/section\u003e","brand":"Borowski Race Engines","offers":[{"title":"Yes","offer_id":38161578786990,"sku":"BRE043554-EE-BH","price":1595.0,"currency_code":"USD","in_stock":true},{"title":"No - Bare","offer_id":38161578819758,"sku":"","price":1300.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0248\/9809\/products\/45355078274_2ed2e250a1_o.jpg?v=1613582549"},{"product_id":"dart-pro-1-cnc-ported-355-bbc-cylinder-heads","title":"Dart Pro 1 CNC Ported, 360 BBC Cylinder Heads, Assembled","description":"\u003cdiv style=\"text-align: center;\"\u003e\u003cstrong\u003e PRICING IS PER PAIR\u003c\/strong\u003e\u003c\/div\u003e\n\u003cdiv style=\"text-align: center;\"\u003e \u003cbr\u003e\n\u003c\/div\u003e\n\u003cp\u003eThese are the same heads as we use in our Big Block builds like this one. \u003c\/p\u003e\n\u003cp\u003e\u003ciframe height=\"1138\" width=\"640\" src=\"https:\/\/player.vimeo.com\/video\/802167565?h=ab8a086331\"\u003e\u003c\/iframe\u003e\u003c\/p\u003e\n\u003cp\u003eYou therefore know that we like them and they work. Another big advantage is that we almost always have them in stock.\u003c\/p\u003e\n\u003cp\u003eWe buy these Dart Pro 1 BBC cylinder heads as porter castings so that we can do the machining on our own CNCs.  The finished heads are therefore not the same as the Dart's.  The Dart machined heads are great, but ours flow even better and in our experience, make more horsepower.\u003c\/p\u003e\n\u003cp\u003eHow do we get these results? Because we are not doing high volume production like Dart, we are constantly tweeking the port designs on the heads we run through our Rottler 5-axis CNC.  The net result is that the geometry of our finished cylinder heads is constantly evolving whereas an OE's design will be more static.  Another big advantage we have is our our Newen CNC seat \u0026amp; guide machine.  Check out the videos below to see these machines at work and the advantages the Newen brings to cylinder head machining.  Why don't all shops have a Newen? Simple - they cost a ton of money.\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003eThe assembled heads are available assembled for either hydraulic or mechanical cam applications. The mechanical cam standard version uses Dart Severe Duty stainless steel intake valves and Dart Inconel exhaust valves. Manley Severe Duty valves are standard for the hydraulic cam version. We use Manley spring kits with 10 degree hardened steel locks and titanium retainers for both versions.  Spring set specifications the hydraulic roller and mechanical cam versions are as shown below:\u003c\/p\u003e\n\u003cp\u003eHydraulic: Professional, \u003cspan\u003eDual Spring, \u003c\/span\u003e507 lb\/in Spring Rate, 1.190 inch Coil Bind, 1.550 inch OD\u003c\/p\u003e\n\u003cp\u003eMechanical:  NexTek, Dual Spring, 604 lb\/in Spring Rate, 1.150 inch Coil Bind, 1.640 inch OD\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003ePlease call us with any questions at 815-725-2727.\u003c\/p\u003e\n\u003cp\u003eROCKER ARMS IN PHOTOS ARE NOT INCLUDED\u003c\/p\u003e\n\u003cp\u003ePayments Type Accepted:  Cash, credit card, wire transfer\u003c\/p\u003e\n\u003cp\u003e\u003ciframe height=\"360\" width=\"640\" src=\"https:\/\/player.vimeo.com\/video\/1066132456?h=0edcae79b8\" title=\"vimeo-player\"\u003e\u003c\/iframe\u003e\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003ciframe width=\"560\" height=\"315\" src=\"https:\/\/www.youtube.com\/embed\/Vi_TFjKdPn8\" title=\"YouTube video player\"\u003e\u003c\/iframe\u003e\u003c\/p\u003e","brand":"Dart","offers":[{"title":"Hydraulic","offer_id":43837455237332,"sku":"BRE043603-MAN-HYD","price":4435.0,"currency_code":"USD","in_stock":true},{"title":"Mechanical","offer_id":43837455270100,"sku":"BRE043604-SOLID","price":4895.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0248\/9809\/files\/53322611977_474ec1997f_o.jpg?v=1729375684"},{"product_id":"cnc-ported-afr-12-degree-6-bolt-ls3-cylinder-head-package","title":"CNC Ported AFR 12 Degree, 6-Bolt LS3 Cylinder Heads - Assembled","description":"\u003cp class=\"MsoNormal\"\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eAFR Mongoose LS3 heads heads bring a lot to the party with their 12 degree, 6-bolt design. We buy these heads as porter castings and machine them to perfection on our CNCs.  The shapes we impart to the ports and combustion chambers reflect our years of experience on our own engine builds.  \u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"MsoNormal\"\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eWe know what makes power and also survives the beating of competition.  It's not chasing peak air flow at max lift by excessively cutting away the metal around the valve guides. Peak air flow occurs at only one instant in the cycle. Our focus is more on average air flow across the entire cycle. For spring packages with 0.650 inch max-lift, quoting a peak airflow at 0.800 inches is irrelevant.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"MsoNormal\"\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eOf paramount importance for us is that our heads don't break and wreck our engines.  We therefore do not chase flow at the expense of weakening the heads mechanical integrity. That's a concern that non-engine builders don't share. \u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"MsoNormal\"\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eOur process for machining these heads includes CNC porting and combustion chamber machining on our 5-axis with CNC valve job and bowl bowl blend on our Newen CNC seat \u0026amp; guide machine (see videos down below). The 6-bolt configuaration is standard but we can remove the 6-bolt provision upon request.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"MsoNormal\"\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eThe results we get are as shown in the Tables immediately below.\u003c\/span\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003e\u003c\/span\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003ctable style=\"border-collapse: collapse; width: 384pt;\" width=\"518\" cellspacing=\"0\" cellpadding=\"0\" border=\"0\"\u003e\n\u003ccolgroup\u003e \u003ccol style=\"width: 51pt;\" width=\"68\"\u003e \u003ccol style=\"mso-width-source: userset; mso-width-alt: 1689; width: 37pt;\" span=\"9\" width=\"50\"\u003e \u003c\/colgroup\u003e\n\u003ctbody\u003e\n\u003ctr style=\"height: 14.65pt;\" height=\"20\"\u003e\n\u003ctd style=\"height: 14.65pt; width: 51pt;\" width=\"68\" height=\"20\"\u003eLIFT\u003c\/td\u003e\n\u003ctd style=\"width: 37pt;\" width=\"50\" align=\"right\" class=\"xl65\"\u003e0.1\u003c\/td\u003e\n\u003ctd style=\"width: 37pt;\" width=\"50\" align=\"right\" class=\"xl65\"\u003e0.2\u003c\/td\u003e\n\u003ctd style=\"width: 37pt;\" width=\"50\" align=\"right\" class=\"xl65\"\u003e0.3\u003c\/td\u003e\n\u003ctd style=\"width: 37pt;\" width=\"50\" align=\"right\" class=\"xl65\"\u003e0.4\u003c\/td\u003e\n\u003ctd style=\"width: 37pt;\" width=\"50\" align=\"right\" class=\"xl65\"\u003e0.5\u003c\/td\u003e\n\u003ctd style=\"width: 37pt;\" width=\"50\" align=\"right\" class=\"xl65\"\u003e0.6\u003c\/td\u003e\n\u003ctd style=\"width: 37pt;\" width=\"50\" align=\"right\" class=\"xl65\"\u003e0.7\u003c\/td\u003e\n\u003ctd style=\"width: 37pt;\" width=\"50\" align=\"right\" class=\"xl65\"\u003e0.8\u003c\/td\u003e\n\u003ctd style=\"width: 37pt;\" width=\"50\" align=\"right\" class=\"xl65\"\u003e0.9\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 15.75pt;\" height=\"21\"\u003e\n\u003ctd style=\"height: 15.75pt;\" class=\"xl67\" height=\"21\"\u003eIntake\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl66\"\u003e75\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl66\"\u003e163\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl66\"\u003e241\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl66\"\u003e293\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl66\"\u003e340\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl66\"\u003e367\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl66\"\u003e380\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl66\"\u003e358\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl66\"\u003e362\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 15.75pt;\" height=\"21\"\u003e\n\u003ctd style=\"height: 15.75pt;\" class=\"xl67\" height=\"21\"\u003eExhaust\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl66\"\u003e58\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl66\"\u003e111\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl66\"\u003e148\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl66\"\u003e186\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl66\"\u003e208\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl66\"\u003e217\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl66\"\u003e225\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl66\"\u003e227\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl66\"\u003e230\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp style=\"text-align: center;\" class=\"MsoNormal\"\u003e \u003c\/p\u003e\n\u003ctable style=\"border-collapse: collapse; width: 156pt;\" width=\"209\" cellspacing=\"0\" cellpadding=\"0\" border=\"0\"\u003e\n\u003ccolgroup\u003e \u003ccol style=\"mso-width-source: userset; mso-width-alt: 4795; width: 105pt;\" width=\"141\"\u003e \u003ccol style=\"width: 51pt;\" width=\"68\"\u003e \u003c\/colgroup\u003e\n\u003ctbody\u003e\n\u003ctr style=\"height: 14.65pt;\" height=\"20\"\u003e\n\u003ctd style=\"height: 14.65pt; width: 156pt; text-align: center;\" width=\"209\" class=\"xl68\" height=\"20\" colspan=\"2\"\u003eKey Dimensions\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 14.25pt;\" height=\"19\"\u003e\n\u003ctd style=\"height: 14.25pt; border-top: none;\" class=\"xl70\" height=\"19\"\u003eIntake Valve\u003c\/td\u003e\n\u003ctd style=\"border-top: none; border-left: none; text-align: right;\" class=\"xl67\"\u003e2.165\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 14.25pt;\" height=\"19\"\u003e\n\u003ctd style=\"height: 14.25pt;\" class=\"xl71\" height=\"19\"\u003eExhaust Valve\u003c\/td\u003e\n\u003ctd style=\"border-left: none; text-align: right;\" class=\"xl65\"\u003e1.600\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 14.25pt;\" height=\"19\"\u003e\n\u003ctd style=\"height: 14.25pt;\" class=\"xl71\" height=\"19\"\u003eCombusion Chamber\u003c\/td\u003e\n\u003ctd style=\"border-left: none; text-align: right;\" class=\"xl65\"\u003e67cc\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 14.25pt;\" height=\"19\"\u003e\n\u003ctd style=\"height: 14.25pt;\" class=\"xl71\" height=\"19\"\u003eIntake Port\u003c\/td\u003e\n\u003ctd style=\"border-left: none; text-align: right;\" class=\"xl65\"\u003e260cc\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 14.65pt;\" height=\"20\"\u003e\n\u003ctd style=\"height: 14.65pt;\" class=\"xl72\" height=\"20\"\u003eExhaust Port\u003c\/td\u003e\n\u003ctd style=\"border-left: none; text-align: right;\" class=\"xl66\"\u003e95cc\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp class=\"MsoNormal\"\u003e \u003c\/p\u003e\n\u003cp class=\"MsoNormal\"\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eWe offer a variety of valve \u0026amp; spring packages for these heads to accomodate both naturally aspirated, boosted applications for use with both hydraulic and mechanical cams. The standard package offers a choice of stainless steel or Inconel exhaust valves. Custom combinations are also available. \u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"MsoNormal\"\u003e\u003cspan style=\"text-decoration: underline;\"\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eStandard Valve \u0026amp; Spring Packages\u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eAFR solid stem valves with high RPM dual springs, titanium retainers,  0.650 inch max lift.\u003c\/span\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003e\u003c\/span\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eAnd yes, we eat our own cooking.  This package is what we are now using on our \u003ca href=\"https:\/\/borowskirace.com\/products\/720-hp-naturally-aspirated-408-cid-hydraulic-roller-ls-street-engine-complete?variant=45584077947092\" title=\"720 hp LS\" rel=\"noopener\" target=\"_blank\"\u003e720hp, 408ci LS\u003c\/a\u003e  as can be seen in the video below.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003e\u003ciframe title=\"vimeo-player\" src=\"https:\/\/player.vimeo.com\/video\/1004948624?h=4f1838e475\" width=\"640\" height=\"360\"\u003e\u003c\/iframe\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003ePayment Types Accepted: Cash, Credit Card, Wire Transfer, ACH\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eBuilt by people who love motorsports for people who love motorsports\u003c\/span\u003e\u003c\/em\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003e\u003ciframe width=\"560\" height=\"315\" src=\"https:\/\/www.youtube.com\/embed\/tswpi1ULaOY?si=5zUyRHFE72K0sgvj\" title=\"YouTube video player\"\u003e\u003c\/iframe\u003e\u003ciframe width=\"560\" height=\"315\" src=\"https:\/\/www.youtube.com\/embed\/Vi_TFjKdPn8?si=erUbh-PAjMoG2RZf\" title=\"YouTube video player\"\u003e\u003c\/iframe\u003e\u003c\/span\u003e\u003c\/em\u003e\u003c\/strong\u003e\u003c\/p\u003e","brand":"Airflow Research","offers":[{"title":"Stainless Steel","offer_id":45757228613844,"sku":"BRE043590-3AB","price":3375.0,"currency_code":"USD","in_stock":true},{"title":"Inconel","offer_id":45757228646612,"sku":"BRE043591-3AB-INC","price":3750.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0248\/9809\/files\/AFRheadson5-axissq.jpg?v=1736545220"},{"product_id":"all-pro-cylinder-solid-ls-heads-mechanical-cam-ferrea-titanium-valves","title":"All Pro Cylinder Solid LS7 Heads - Mechanical Cam, Titanium Valves","description":"\u003cp\u003e\u003cspan\u003eThis is the head we use for all of our big boost, billet block LS engines with no water. The 12-4 All Pro solid casting features reinforced exhaust flange, Borowski custom CNC port and chamber design, custom Ferrea titanium intake \u0026amp; exhaust valves.The spring kit features Manley NexTek valve springs (800 lbs.\/in. rate; 1.130 in. coil bind height), Manley machined 10 degree bead locks and Manley titanium retainers. The heads are amazingly strong and here's why:\u003c\/span\u003e\u003cbr\u003e\u003cbr\u003e\u003cspan\u003e- 100% virgin Alcoa aluminum ingot with no remelt\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e- Heads have been HIP treated (hot isostatic pressing) for greater strength and dimensional stability\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e- Up to 1 inch deck thickness, 0.75 inch minimum\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e- Enhanced six-bolt design\u003c\/span\u003e\u003cbr\u003e\u003cbr\u003eThese All Pro LS7 cylinder heads come with shaft mount rocker provisions. \u003cspan\u003eOur custom CNC work brings them to their maximum performance.  B\u003c\/span\u003e\u003cspan\u003eeing cast heads, these qualify for a 50 lb weight reduction in several race classes.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e\u003ciframe title=\"vimeo-player\" src=\"https:\/\/player.vimeo.com\/video\/826510356?h=a3af672fc8\" width=\"640\" height=\"360\" frameborder=\"0\" allowfullscreen=\"\"\u003e\u003c\/iframe\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eCall us at 815-725-2727 with any questions.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003ePriced per pair.\u003c\/span\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003eLearn more about All Pro heads from Bob Williams, owner of All Pro Cylinder Heads and check out a set of the dry version of these heads at work on a ProSpeed's dyno.\u003c\/p\u003e\n\u003cp\u003e\u003ciframe title=\"YouTube video player\" src=\"https:\/\/www.youtube.com\/embed\/NFyY2e6Plb8\" height=\"315\" width=\"560\" allowfullscreen=\"\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture\" frameborder=\"0\"\u003e\u003c\/iframe\u003e \u003c\/p\u003e\n\u003cp\u003e\u003ciframe title=\"YouTube video player\" src=\"https:\/\/www.youtube.com\/embed\/ZPMAXjOlY1A\" height=\"315\" width=\"560\" allowfullscreen=\"\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture\" frameborder=\"0\"\u003e\u003c\/iframe\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003ePayment types accepted: wire transfer, ACH, cash, credit cards with surcharge\u003c\/p\u003e","brand":"All Pro Cylinder Heads","offers":[{"title":"Default Title","offer_id":45677208273108,"sku":"BRE043574S-900T","price":9895.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0248\/9809\/files\/AllProSolid1-sq.jpg?v=1727624201"},{"product_id":"bre-cncd-brodix-cathedral-port-ls-heads-for-boost","title":"BRE CNC'd Brodix 13.5 Degree Cathedral Port LS Heads for Boost","description":"\u003cp\u003eWe receive these 6-bolt, cathedral port heads as porter castings from Brodix and put them through our machining processes imparting our own designs at each stage. Brodix has incorporated a 13.5 degree valve angle with the Brodix steel intake and Inconel exhaust valves sized at 2.100 and 1.600 inches respectively. The \u003cstrong\u003eMade in USA\u003c\/strong\u003e castings are produced from virgin A-356 aluminum alloy and have a thick deck to handle nitrous and blown applications. As you can see in the video below, these heads can also be great for naturally aspirated applications. \u003c\/p\u003e\n\u003cp\u003e\u003ciframe width=\"560\" height=\"315\" src=\"https:\/\/www.youtube.com\/embed\/m6vIopHqQMo?si=5861gYdVIB2uw65-\" title=\"YouTube video player\"\u003e\u003c\/iframe\u003e\u003c\/p\u003e\n\u003cp\u003eWhile some head porters chase maximum flow numbers, we are more interested in finding optimum power without compromising the head's strength and durability. For example, we leave more metal around the valve guide to ensure longevity.  The machining steps we do include more than just the 5-axis CNC work.  Our Newen CNC seat \u0026amp; guide machine does a precision valve job and bowl blending in a single step.with incredible precision.  Our Berco mill ensures a perfectly flat deck with hand touch up steps of chamfering and deburring.\u003c\/p\u003e\n\u003cp\u003eThe finished head has port volumes of 290cc on the intake and 109cc on the exhaust.  By our measurements, intake flow is 335cfm at 0.600 inch lift with exhaust at 224cfm. We have a single technician perform all our flow testing to reduce test variability  Air flow results will vary based on operator, flow bench and other variables.  We therefore advise against using anyone's reported numbers as a precise means of comparison. Our results are used primarily for internal comparisons with the true performance arbiter being our engine dyno.\u003c\/p\u003e\n\u003cp\u003eThe Borowski-Manley dual LS valve spring kit includes:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan style=\"font-size: 0.875rem;\"\u003edual Manley NexTek valve springs with 1.340 in. outside diameter, 394 lbs.\/in. rate, and 1.050 inch Coil Bind Height, \u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan style=\"font-size: 0.875rem;\"\u003eManley titanium valve spring retainers - Dual, Tall Style, 7 Degree, Titanium, 1.200 in. Retainer O.D, \u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan style=\"font-size: 0.875rem;\"\u003eManley valve spring locators - ID: .567\", OD: 1.320\", Thickness: .035\", Shoulder Diameter: .715\", \u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan style=\"font-size: 0.875rem;\"\u003eManley machined bead valve locks with valve stem seals. \u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cimg height=\"277\" width=\"508\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0248\/9809\/files\/man-26361634ks_xl.jpg?v=1727639827\" alt=\"\"\u003e\u003c\/p\u003e\n\u003cp\u003eIf this spring kit is not exactly what you need, please call us at 815-725-2727 and we will look to get you a different set that better suits your needs\u003c\/p\u003e\n\u003cp\u003eYou might also like to watch the videos below showing the engine in this photo set on our dyno along with a couple of machining videos:\u003c\/p\u003e\n\u003cp\u003e\u003cspan style=\"text-decoration: underline;\"\u003eDyno Video\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003ciframe height=\"360\" width=\"640\" src=\"https:\/\/player.vimeo.com\/video\/1014007525?h=4d2d1101bf\" title=\"vimeo-player\"\u003e\u003c\/iframe\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan style=\"text-decoration: underline;\"\u003eClose Up Spin Video\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003ciframe title=\"vimeo-player\" src=\"https:\/\/player.vimeo.com\/video\/1050824433?h=2afe126d08\" width=\"640\" height=\"360\"\u003e\u003c\/iframe\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan style=\"text-decoration: underline;\"\u003eMachining Videos\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003ciframe title=\"YouTube video player\" src=\"https:\/\/www.youtube.com\/embed\/FX7HCBxF88g?si=pI_lS2WFLwPjzDRO\" height=\"315\" width=\"560\"\u003e\u003c\/iframe\u003e\u003c\/p\u003e\n\u003cp\u003e\u003ciframe width=\"560\" height=\"315\" src=\"https:\/\/www.youtube.com\/embed\/Vi_TFjKdPn8?si=c6z0gC1-Sq6s-3Yt\" title=\"YouTube video player\"\u003e\u003c\/iframe\u003e\u003c\/p\u003e\n\u003cp\u003ePayment Types Accepted: Cash, wire transfer, ACH, credit card with surcharge\u003c\/p\u003e","brand":"Brodix","offers":[{"title":"Default Title","offer_id":45677371261140,"sku":"BRE043568","price":4175.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0248\/9809\/files\/BrodixBR1-1sq.jpg?v=1727640833"},{"product_id":"cnc-ported-cid-6-bolt-lt-cylinder-heads-assembled","title":"CNC-Ported CID, 6-Bolt, LT4 Cylinder Heads, Assembled","description":"\u003cp class=\"MsoNormal\"\u003e\u003cspan style=\"font-size: 16px;\"\u003eOur CNC-ported GM LT heads are pretty darn good. These CID heads are better and by a lot! Here's why: \u003c\/span\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli class=\"MsoNormal\"\u003e\u003cspan style=\"font-size: 16px;\"\u003eWe buy these heads as porter castings which allows us to impart whatever design we like to the runners and combustion chamber.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli class=\"MsoNormal\"\u003e\u003cspan style=\"font-size: 16px;\"\u003eThese heads were designed from ground up for competition, not transportation\u003c\/span\u003e\u003c\/li\u003e\n\u003cli class=\"MsoNormal\"\u003e\u003cspan style=\"font-size: 16px;\"\u003eThey are made in the USA using premium aluminum alloy with no  remelt under the watchful eye of CID's owner\u003c\/span\u003e\u003c\/li\u003e\n\u003cli class=\"MsoNormal\"\u003e\u003cspan style=\"font-size: 16px;\"\u003eThe deck is about 0.25 inch thicker than OE heads\u003c\/span\u003e\u003c\/li\u003e\n\u003cli class=\"MsoNormal\"\u003e\n\u003cspan style=\"font-size: 16px;\"\u003eThe six-bolt design provides a lot more clamping power if paired with a six-bolt block.  These are pretty rare now but should be coming from the usual suspects in the foreseeable future.\u003c\/span\u003e\u003cspan style=\"font-size: 16px;\"\u003e\u003c\/span\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp class=\"MsoNormal\"\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eWe know what makes power and also survives the beating of competition.  It's not chasing peak air flow at max lift by excessively cutting away the metal around the valve guides. Peak air flow occurs at only one instant in the cycle. Our focus is more on average air flow across the entire cycle. For spring packages with 0.650 inch max-lift, quoting a peak airflow at 0.800 inches is irrelevant. \u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"MsoNormal\"\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eOf paramount importance for us is that our heads don't break and wreck our engines.  We therefore do not chase flow at the expense of weakening the heads mechanical integrity. That's a concern that non-engine builders don't share. \u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"MsoNormal\"\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eOur process for machining these heads starts with CNC porting and combustion chamber machining on our 5-axis. This is followed by CNC valve jobbing and bowl blending in a single operation on our Newen CNC seat \u0026amp; guide machine (see video down below). \u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"MsoNormal\"\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eThe air flow results we get are as shown in the Table immediately below.\u003c\/span\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003e\u003c\/span\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cdiv data-ccp-timestamp=\"1737492112015\"\u003e\n\u003cdiv data-ccp-timestamp=\"1737492112015\"\u003e\n\u003ctable style=\"border-collapse: collapse; width: 375pt;\" width=\"501\" cellspacing=\"0\" cellpadding=\"0\" border=\"0\"\u003e\n\u003ccolgroup\u003e \u003ccol style=\"mso-width-source: userset; mso-width-alt: 2338; width: 51pt;\" width=\"69\"\u003e \u003ccol style=\"mso-width-source: userset; mso-width-alt: 1621; width: 36pt;\" span=\"9\" width=\"48\"\u003e \u003c\/colgroup\u003e\n\u003ctbody\u003e\n\u003ctr style=\"height: 14.65pt;\" height=\"20\"\u003e\n\u003ctd style=\"height: 14.65pt; width: 51pt;\" width=\"69\" class=\"xl72\" height=\"20\"\u003eValve Lift:\u003c\/td\u003e\n\u003ctd style=\"border-left: none; width: 36pt;\" width=\"48\" align=\"right\" class=\"xl65\"\u003e0.1\u003c\/td\u003e\n\u003ctd style=\"width: 36pt;\" width=\"48\" align=\"right\" class=\"xl66\"\u003e0.2\u003c\/td\u003e\n\u003ctd style=\"width: 36pt;\" width=\"48\" align=\"right\" class=\"xl66\"\u003e0.3\u003c\/td\u003e\n\u003ctd style=\"width: 36pt;\" width=\"48\" align=\"right\" class=\"xl66\"\u003e0.4\u003c\/td\u003e\n\u003ctd style=\"width: 36pt;\" width=\"48\" align=\"right\" class=\"xl66\"\u003e0.5\u003c\/td\u003e\n\u003ctd style=\"width: 36pt;\" width=\"48\" align=\"right\" class=\"xl66\"\u003e0.6\u003c\/td\u003e\n\u003ctd style=\"width: 36pt;\" width=\"48\" align=\"right\" class=\"xl66\"\u003e0.7\u003c\/td\u003e\n\u003ctd style=\"width: 36pt;\" width=\"48\" align=\"right\" class=\"xl66\"\u003e0.75\u003c\/td\u003e\n\u003ctd style=\"width: 36pt;\" width=\"48\" align=\"right\" class=\"xl67\"\u003e0.8\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 15.75pt;\" height=\"21\"\u003e\n\u003ctd style=\"height: 15.75pt;\" class=\"xl73\" height=\"21\"\u003eIntake\u003c\/td\u003e\n\u003ctd style=\"border-left: none;\" align=\"right\" class=\"xl75\"\u003e91\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl68\"\u003e157\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl68\"\u003e232\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl68\"\u003e284\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl68\"\u003e331\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl68\"\u003e351\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl68\"\u003e353\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl68\"\u003e358\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl69\"\u003e362\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 16.15pt;\" height=\"22\"\u003e\n\u003ctd style=\"height: 16.15pt;\" class=\"xl74\" height=\"22\"\u003eExhaust\u003c\/td\u003e\n\u003ctd style=\"border-left: none;\" align=\"right\" class=\"xl76\"\u003e52.4\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl70\"\u003e110\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl70\"\u003e151\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl70\"\u003e198\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl70\"\u003e222\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl70\"\u003e230\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl70\"\u003e236\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl70\"\u003e236\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl71\"\u003e236\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cp class=\"MsoNormal\"\u003e \u003c\/p\u003e\n\u003cdiv data-ccp-timestamp=\"1737492514444\"\u003e\n\u003ctable style=\"border-collapse: collapse; width: 148pt;\" width=\"197\" cellspacing=\"0\" cellpadding=\"0\" border=\"0\"\u003e\n\u003ccolgroup\u003e \u003ccol style=\"mso-width-source: userset; mso-width-alt: 4078; width: 90pt;\" width=\"120\"\u003e \u003ccol style=\"mso-width-source: userset; mso-width-alt: 2628; width: 58pt;\" width=\"77\"\u003e \u003c\/colgroup\u003e\n\u003ctbody\u003e\n\u003ctr style=\"height: 14.65pt;\" height=\"20\"\u003e\n\u003ctd style=\"height: 14.65pt; width: 90pt;\" width=\"120\" class=\"xl65\" height=\"20\"\u003eIntake Valve:\u003c\/td\u003e\n\u003ctd style=\"width: 58pt;\" width=\"77\" class=\"xl68\"\u003e2.130\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 15.75pt;\" height=\"21\"\u003e\n\u003ctd style=\"height: 15.75pt;\" class=\"xl66\" height=\"21\"\u003eExhaust Valve:\u003c\/td\u003e\n\u003ctd class=\"xl69\"\u003e1.600\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 16.15pt;\" height=\"22\"\u003e\n\u003ctd style=\"height: 16.15pt;\" class=\"xl66\" height=\"22\"\u003eAfter Intake:\u003c\/td\u003e\n\u003ctd class=\"xl69\"\u003e276cc\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 14.65pt;\" height=\"20\"\u003e\n\u003ctd style=\"height: 14.65pt;\" class=\"xl67\" height=\"20\"\u003eAfter Exhaust:\u003c\/td\u003e\n\u003ctd class=\"xl70\"\u003e110cc\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 14.65pt;\" height=\"20\"\u003e\n\u003ctd style=\"height: 14.65pt;\" class=\"xl67\" height=\"20\"\u003eMax Lift\u003c\/td\u003e\n\u003ctd class=\"xl70\"\u003e0.65\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 14.65pt;\" height=\"20\"\u003e\n\u003ctd style=\"height: 14.65pt;\" class=\"xl67\" height=\"20\"\u003eChamber Volume\u003c\/td\u003e\n\u003ctd class=\"xl70\"\u003e58cc\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/div\u003e\n\u003cp class=\"MsoNormal\"\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eWe offer a variety of valve \u0026amp; spring packages for these heads to accomodate both naturally aspirated, boosted applications for use with both hydraulic and mechanical cams. The standard spring \u0026amp; valve package comes with GM titanium intake and Manley stainless steel exhaust valves with a Manley dual spring kit. Call us at 815-725-2727 to discuss your requirements.\u003c\/span\u003e\u003cspan style=\"text-decoration: underline;\"\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003e\u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"MsoNormal\"\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003ePricing is per pair.\u003c\/span\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cdiv style=\"padding: 177.78% 0 0 0; position: relative;\"\u003e\u003ciframe src=\"https:\/\/player.vimeo.com\/video\/1024822704?title=0\u0026amp;byline=0\u0026amp;portrait=0\u0026amp;badge=0\u0026amp;autopause=0\u0026amp;player_id=0\u0026amp;app_id=58479\" style=\"position: absolute; top: 0; left: 0; width: 100%; height: 100%;\" title=\"5-Axis CNC Porting a CID LT4 Head from a Porter Casting\"\u003e\u003c\/iframe\u003e\u003c\/div\u003e\n\u003cp\u003eStart weight: 34.4 lbs    Finish weight: 31.0 lbs\u003c\/p\u003e\n\u003cp\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003ePayment Types Accepted: Cash, Credit Card, Wire Transfer, ACH\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eBuilt by people who love motorsports for people who love motorsports\u003c\/span\u003e\u003c\/em\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003e\u003ciframe width=\"560\" height=\"315\" src=\"https:\/\/www.youtube.com\/embed\/Vi_TFjKdPn8?si=erUbh-PAjMoG2RZf\" title=\"YouTube video player\"\u003e\u003c\/iframe\u003e\u003c\/span\u003e\u003c\/em\u003e\u003c\/strong\u003e\u003c\/p\u003e","brand":"CID","offers":[{"title":"Default Title","offer_id":46015192531156,"sku":"BRE043605","price":5895.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0248\/9809\/files\/54194641329_e7d8164c95_o.jpg?v=1737495691"},{"product_id":"cnc-ported-afr-cathedral-port-6-bolt-ls-cylinder-head","title":"CNC Ported AFR Cathedral Port, 6-Bolt LS Cylinder Heads - Assembled","description":"\u003cp class=\"MsoNormal\"\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eThese AFR cathedral port heads bring a lot to the party with their 6-bolt design. We buy these heads as porter castings and machine them to perfection on our CNCs.  The shapes we impart to the ports and combustion chambers reflect our years of experience on our own engine builds.  \u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"MsoNormal\"\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eWe know what makes power and also survives the beating of competition.  It's not chasing peak air flow at max lift by excessively cutting away the metal around the valve guides. Peak air flow occurs at only one instant in the cycle. Our focus is more on average air flow across the entire cycle. For spring packages with 0.650 inch max-lift, quoting a peak airflow at 0.800 inches is irrelevant.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"MsoNormal\"\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eOf paramount importance for us is that our cylinder heads don't break and wreck our engines.  We therefore do not chase flow at the expense of weakening the heads mechanical integrity. That's a concern that non-engine builders don't share. \u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"MsoNormal\"\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eOur process for machining heads includes CNC porting and combustion chamber machining on our 5-axis. Our Newen CNC seat \u0026amp; guide machine does the valve job and bowl bowl blending in a single operation. As can be seen in the video below, the Newen's CNC precision simply cannot be matched with traditional seat \u0026amp; Guide machines and hand blending. Being engine builders, we see first-hand how well our port designs are working on the dyno. That too gives us a big advantage over pure head porters.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"MsoNormal\"\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eThe results we get are as shown in the Tables immediately below.\u003c\/span\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003e\u003c\/span\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003ctable border=\"0\" cellpadding=\"0\" cellspacing=\"0\" width=\"518\" style=\"border-collapse: collapse; width: 512px; height: 73.5015px;\"\u003e\n\u003ccolgroup\u003e \u003ccol width=\"68\" style=\"width: 68px;\"\u003e \u003ccol width=\"50\" span=\"9\" style=\"width: 49px;\"\u003e \u003c\/colgroup\u003e\n\u003ctbody\u003e\n\u003ctr height=\"20\" style=\"height: 24.5005px;\"\u003e\n\u003ctd height=\"20\" width=\"68\" style=\"height: 24.5005px; width: 51pt;\"\u003eLIFT\u003c\/td\u003e\n\u003ctd class=\"xl65\" align=\"right\" width=\"50\" style=\"width: 37pt; height: 24.5005px;\"\u003e0.1\u003c\/td\u003e\n\u003ctd class=\"xl65\" align=\"right\" width=\"50\" style=\"width: 37pt; height: 24.5005px;\"\u003e0.2\u003c\/td\u003e\n\u003ctd class=\"xl65\" align=\"right\" width=\"50\" style=\"width: 37pt; height: 24.5005px;\"\u003e0.3\u003c\/td\u003e\n\u003ctd class=\"xl65\" align=\"right\" width=\"50\" style=\"width: 37pt; height: 24.5005px;\"\u003e0.4\u003c\/td\u003e\n\u003ctd class=\"xl65\" align=\"right\" width=\"50\" style=\"width: 37pt; height: 24.5005px;\"\u003e0.5\u003c\/td\u003e\n\u003ctd class=\"xl65\" align=\"right\" width=\"50\" style=\"width: 37pt; height: 24.5005px;\"\u003e0.6\u003c\/td\u003e\n\u003ctd class=\"xl65\" align=\"right\" width=\"50\" style=\"width: 37pt; height: 24.5005px;\"\u003e0.7\u003c\/td\u003e\n\u003ctd class=\"xl65\" align=\"right\" width=\"50\" style=\"width: 37pt; height: 24.5005px;\"\u003e0.8\u003c\/td\u003e\n\u003ctd class=\"xl65\" align=\"right\" width=\"50\" style=\"width: 37pt; height: 24.5005px;\"\u003e0.9\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr height=\"21\" style=\"height: 24.5005px;\"\u003e\n\u003ctd height=\"21\" class=\"xl67\" style=\"height: 24.5005px;\"\u003eIntake\u003c\/td\u003e\n\u003ctd style=\"height: 24.5005px;\" class=\"xl66\" align=\"right\"\u003e71\u003c\/td\u003e\n\u003ctd style=\"height: 24.5005px;\" class=\"xl66\" align=\"right\"\u003e132\u003c\/td\u003e\n\u003ctd style=\"height: 24.5005px;\" class=\"xl66\" align=\"right\"\u003e187\u003c\/td\u003e\n\u003ctd style=\"height: 24.5005px;\" class=\"xl66\" align=\"right\"\u003e244\u003c\/td\u003e\n\u003ctd style=\"height: 24.5005px;\" class=\"xl66\" align=\"right\"\u003e286\u003c\/td\u003e\n\u003ctd style=\"height: 24.5005px;\" class=\"xl66\" align=\"right\"\u003e313\u003c\/td\u003e\n\u003ctd style=\"height: 24.5005px;\" class=\"xl66\" align=\"right\"\u003e331\u003c\/td\u003e\n\u003ctd style=\"height: 24.5005px;\" class=\"xl66\" align=\"right\"\u003e340\u003c\/td\u003e\n\u003ctd style=\"height: 24.5005px;\" class=\"xl66\" align=\"right\"\u003e340\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr height=\"21\" style=\"height: 24.5005px;\"\u003e\n\u003ctd height=\"21\" class=\"xl67\" style=\"height: 24.5005px;\"\u003eExhaust\u003c\/td\u003e\n\u003ctd style=\"height: 24.5005px;\" class=\"xl66\" align=\"right\"\u003e56\u003c\/td\u003e\n\u003ctd style=\"height: 24.5005px;\" class=\"xl66\" align=\"right\"\u003e107\u003c\/td\u003e\n\u003ctd style=\"height: 24.5005px;\" class=\"xl66\" align=\"right\"\u003e164\u003c\/td\u003e\n\u003ctd style=\"height: 24.5005px;\" class=\"xl66\" align=\"right\"\u003e198\u003c\/td\u003e\n\u003ctd style=\"height: 24.5005px;\" class=\"xl66\" align=\"right\"\u003e224\u003c\/td\u003e\n\u003ctd style=\"height: 24.5005px;\" class=\"xl66\" align=\"right\"\u003e230\u003c\/td\u003e\n\u003ctd style=\"height: 24.5005px;\" class=\"xl66\" align=\"right\"\u003e239\u003c\/td\u003e\n\u003ctd style=\"height: 24.5005px;\" class=\"xl66\" align=\"right\"\u003e244\u003c\/td\u003e\n\u003ctd style=\"height: 24.5005px;\" class=\"xl66\" align=\"right\"\u003e244\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp style=\"text-align: -webkit-right;\"\u003e \u003c\/p\u003e\n\u003cp class=\"MsoNormal\" style=\"text-align: center;\"\u003e \u003c\/p\u003e\n\u003ctable border=\"0\" cellpadding=\"0\" cellspacing=\"0\" width=\"209\" style=\"border-collapse: collapse; width: 156pt; height: 171.503px;\"\u003e\n\u003ccolgroup\u003e \u003ccol width=\"141\" style=\"mso-width-source: userset; mso-width-alt: 4795; width: 105pt;\"\u003e \u003ccol width=\"68\" style=\"width: 51pt;\"\u003e \u003c\/colgroup\u003e\n\u003ctbody\u003e\n\u003ctr height=\"20\" style=\"height: 24.5005px;\"\u003e\n\u003ctd colspan=\"2\" height=\"20\" class=\"xl68\" width=\"209\" style=\"height: 24.5005px; width: 156pt; text-align: center;\"\u003eKey Dimensions\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr height=\"19\" style=\"height: 24.5005px;\"\u003e\n\u003ctd height=\"19\" class=\"xl70\" style=\"height: 24.5005px; border-top: none;\"\u003eIntake Valve\u003c\/td\u003e\n\u003ctd class=\"xl67\" style=\"border-top: none; border-left: none; text-align: right; height: 24.5005px;\"\u003e2.165\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr height=\"19\" style=\"height: 24.5005px;\"\u003e\n\u003ctd height=\"19\" class=\"xl71\" style=\"height: 24.5005px;\"\u003eExhaust Valve\u003c\/td\u003e\n\u003ctd class=\"xl65\" style=\"border-left: none; text-align: right; height: 24.5005px;\"\u003e1.600\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr height=\"19\" style=\"height: 49.001px;\"\u003e\n\u003ctd height=\"19\" class=\"xl71\" style=\"height: 49.001px;\"\u003eCombusion Chamber\u003c\/td\u003e\n\u003ctd class=\"xl65\" style=\"border-left: none; text-align: right; height: 49.001px;\"\u003e62cc\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr height=\"19\" style=\"height: 24.5005px;\"\u003e\n\u003ctd height=\"19\" class=\"xl71\" style=\"height: 24.5005px;\"\u003eIntake Port\u003c\/td\u003e\n\u003ctd class=\"xl65\" style=\"border-left: none; text-align: right; height: 24.5005px;\"\u003e233cc\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr height=\"20\" style=\"height: 24.5005px;\"\u003e\n\u003ctd height=\"20\" class=\"xl72\" style=\"height: 24.5005px;\"\u003eExhaust Port\u003c\/td\u003e\n\u003ctd class=\"xl66\" style=\"border-left: none; text-align: right; height: 24.5005px;\"\u003e90cc\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp class=\"MsoNormal\"\u003e \u003c\/p\u003e\n\u003cp class=\"MsoNormal\"\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eWe offer a variety of valve \u0026amp; spring packages for these heads to accomodate both naturally aspirated, boosted applications for use with both hydraulic and mechanical cams. The standard package offers a choice of stainless steel or Inconel exhaust valves. Custom combinations are also available. \u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"MsoNormal\"\u003e\u003cspan style=\"text-decoration: underline;\"\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eStandard Valve \u0026amp; Spring Packages\u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eAFR solid stem valves with high RPM dual springs, titanium retainers,  0.650 inch max lift.\u003c\/span\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003e\u003c\/span\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003ePayment Types Accepted: Cash, Credit Card, Wire Transfer, ACH\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eBuilt by people who love motorsports for people who love motorsports\u003c\/span\u003e\u003c\/em\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003e\u003ciframe title=\"YouTube video player\" src=\"https:\/\/www.youtube.com\/embed\/tswpi1ULaOY?si=5zUyRHFE72K0sgvj\" height=\"315\" width=\"560\"\u003e\u003c\/iframe\u003e\u003ciframe title=\"YouTube video player\" src=\"https:\/\/www.youtube.com\/embed\/Vi_TFjKdPn8?si=erUbh-PAjMoG2RZf\" height=\"315\" width=\"560\"\u003e\u003c\/iframe\u003e\u003c\/span\u003e\u003c\/em\u003e\u003c\/strong\u003e\u003c\/p\u003e","brand":"Airflow Research","offers":[{"title":"Stainless Steel","offer_id":46024870199508,"sku":"BRE043590-1AB","price":3375.0,"currency_code":"USD","in_stock":true},{"title":"Inconel","offer_id":46024870232276,"sku":"BRE043590-1AB-INC","price":3750.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0248\/9809\/files\/AFRLS1sq.jpg?v=1737911488"},{"product_id":"cnc-ported-gm-lt4-cylinder-heads-assembled","title":"LT1\/LT4 Cylinder Head Porting \u0026 Upgrade Service","description":"\u003cp class=\"MsoNormal\"\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eOur CNC-porting of GM LT heads significantly improves airflow of these heads. The stock LT heads are known to have valve guide wear issues. We replace the factory guides with CHE valve guides made from CHE's proprietary bronze alloy. This extends the heads' longevity.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"MsoNormal\"\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eWe know what makes power and also survives the beating of competition.  It's not chasing peak air flow at max lift by excessively cutting away the metal around the valve guides. Peak air flow occurs at only one instant in the cycle. Our focus is more on average air flow across the entire cycle. For spring packages with 0.650 inch max-lift, quoting a peak airflow at 0.800 inches is irrelevant. \u003c\/span\u003e\u003c\/p\u003e\n\u003cul\u003e\u003c\/ul\u003e\n\u003cp class=\"MsoNormal\"\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eOf paramount importance for us is that our heads don't break and wreck our engines.  We therefore do not chase flow at the expense of weakening the heads mechanical integrity. That's a concern that non-engine builders don't share.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"MsoNormal\"\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eWe will disassemble and clean your heads upon arrival. Our process for machining these heads starts with CNC porting on our 5-axis. This is followed by CNC valve jobbing and bowl blending in a single operation on our Newen CNC seat \u0026amp; guide machine (see video down below). \u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"MsoNormal\"\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eThe air flow results we get are as shown in the Table immediately below.\u003c\/span\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003e\u003c\/span\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cdiv data-ccp-timestamp=\"1737492112015\"\u003e\n\u003cdiv data-ccp-timestamp=\"1737492112015\"\u003e\n\u003ctable border=\"0\" cellpadding=\"0\" cellspacing=\"0\" width=\"501\" style=\"border-collapse: collapse; width: 375pt;\"\u003e\n\u003ccolgroup\u003e \u003ccol width=\"69\" style=\"mso-width-source: userset; mso-width-alt: 2338; width: 51pt;\"\u003e \u003ccol width=\"48\" span=\"9\" style=\"mso-width-source: userset; mso-width-alt: 1621; width: 36pt;\"\u003e \u003c\/colgroup\u003e\n\u003ctbody\u003e\n\u003ctr height=\"20\" style=\"height: 14.65pt;\"\u003e\n\u003ctd height=\"20\" class=\"xl72\" width=\"69\" style=\"height: 14.65pt; width: 51pt;\"\u003eValve Lift:\u003c\/td\u003e\n\u003ctd class=\"xl65\" align=\"right\" width=\"48\" style=\"border-left: none; width: 36pt;\"\u003e0.1\u003c\/td\u003e\n\u003ctd class=\"xl66\" align=\"right\" width=\"48\" style=\"width: 36pt;\"\u003e0.2\u003c\/td\u003e\n\u003ctd class=\"xl66\" align=\"right\" width=\"48\" style=\"width: 36pt;\"\u003e0.3\u003c\/td\u003e\n\u003ctd class=\"xl66\" align=\"right\" width=\"48\" style=\"width: 36pt;\"\u003e0.4\u003c\/td\u003e\n\u003ctd class=\"xl66\" align=\"right\" width=\"48\" style=\"width: 36pt;\"\u003e0.5\u003c\/td\u003e\n\u003ctd class=\"xl66\" align=\"right\" width=\"48\" style=\"width: 36pt;\"\u003e0.6\u003c\/td\u003e\n\u003ctd class=\"xl66\" align=\"right\" width=\"48\" style=\"width: 36pt;\"\u003e0.7\u003c\/td\u003e\n\u003ctd class=\"xl66\" align=\"right\" width=\"48\" style=\"width: 36pt;\"\u003e0.75\u003c\/td\u003e\n\u003ctd class=\"xl67\" align=\"right\" width=\"48\" style=\"width: 36pt;\"\u003e0.8\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr height=\"21\" style=\"height: 15.75pt;\"\u003e\n\u003ctd height=\"21\" class=\"xl73\" style=\"height: 15.75pt;\"\u003eIntake\u003c\/td\u003e\n\u003ctd class=\"xl75\" align=\"right\" style=\"border-left: none;\"\u003e91\u003c\/td\u003e\n\u003ctd class=\"xl68\" align=\"right\"\u003e160\u003c\/td\u003e\n\u003ctd class=\"xl68\" align=\"right\"\u003e240\u003c\/td\u003e\n\u003ctd class=\"xl68\" align=\"right\"\u003e297\u003c\/td\u003e\n\u003ctd class=\"xl68\" align=\"right\"\u003e335\u003c\/td\u003e\n\u003ctd class=\"xl68\" align=\"right\"\u003e358\u003c\/td\u003e\n\u003ctd class=\"xl68\" align=\"right\"\u003e375\u003c\/td\u003e\n\u003ctd class=\"xl68\" align=\"right\"\u003e382\u003c\/td\u003e\n\u003ctd class=\"xl69\" align=\"right\"\u003e382\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr height=\"22\" style=\"height: 16.15pt;\"\u003e\n\u003ctd height=\"22\" class=\"xl74\" style=\"height: 16.15pt;\"\u003eExhaust\u003c\/td\u003e\n\u003ctd class=\"xl76\" align=\"right\" style=\"border-left: none;\"\u003e69\u003c\/td\u003e\n\u003ctd class=\"xl70\" align=\"right\"\u003e126\u003c\/td\u003e\n\u003ctd class=\"xl70\" align=\"right\"\u003e180\u003c\/td\u003e\n\u003ctd class=\"xl70\" align=\"right\"\u003e198\u003c\/td\u003e\n\u003ctd class=\"xl70\" align=\"right\"\u003e221\u003c\/td\u003e\n\u003ctd class=\"xl70\" align=\"right\"\u003e236\u003c\/td\u003e\n\u003ctd class=\"xl70\" align=\"right\"\u003e246\u003c\/td\u003e\n\u003ctd class=\"xl70\" align=\"right\"\u003e249\u003c\/td\u003e\n\u003ctd class=\"xl71\" align=\"right\"\u003e249\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cp class=\"MsoNormal\"\u003e \u003c\/p\u003e\n\u003cdiv data-ccp-timestamp=\"1737492514444\"\u003e\n\u003ctable border=\"0\" cellpadding=\"0\" cellspacing=\"0\" width=\"197\" style=\"border-collapse: collapse; width: 148pt;\"\u003e\n\u003ccolgroup\u003e \u003ccol width=\"120\" style=\"width: 119px;\"\u003e \u003ccol width=\"77\" style=\"width: 77px;\"\u003e \u003c\/colgroup\u003e\n\u003ctbody\u003e\n\u003ctr height=\"20\" style=\"height: 14.65pt;\"\u003e\n\u003ctd height=\"20\" class=\"xl65\" width=\"120\" style=\"height: 14.65pt; width: 90pt;\"\u003eIntake Valve:\u003c\/td\u003e\n\u003ctd class=\"xl68\" width=\"77\" style=\"width: 58pt;\"\u003e2.126\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr height=\"21\" style=\"height: 15.75pt;\"\u003e\n\u003ctd height=\"21\" class=\"xl66\" style=\"height: 15.75pt;\"\u003eExhaust Valve:\u003c\/td\u003e\n\u003ctd class=\"xl69\"\u003e1.590\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr height=\"22\" style=\"height: 16.15pt;\"\u003e\n\u003ctd height=\"22\" class=\"xl66\" style=\"height: 16.15pt;\"\u003eAfter Intake:\u003c\/td\u003e\n\u003ctd class=\"xl69\"\u003e296cc\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr height=\"20\" style=\"height: 14.65pt;\"\u003e\n\u003ctd height=\"20\" class=\"xl67\" style=\"height: 14.65pt;\"\u003eAfter Exhaust:\u003c\/td\u003e\n\u003ctd class=\"xl70\"\u003e110cc\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr height=\"20\" style=\"height: 14.65pt;\"\u003e\n\u003ctd height=\"20\" class=\"xl67\" style=\"height: 14.65pt;\"\u003eMax Lift\u003c\/td\u003e\n\u003ctd class=\"xl70\"\u003e0.65\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr height=\"20\" style=\"height: 14.65pt;\"\u003e\n\u003ctd height=\"20\" class=\"xl67\" style=\"height: 14.65pt;\"\u003eChamber Volume\u003c\/td\u003e\n\u003ctd class=\"xl70\"\u003e65.5cc\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/div\u003e\n\u003cp class=\"MsoNormal\"\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eThe heads are then reassembled with your original hardware (if useable), or with the optional parts as discussed in the next paragraph.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"MsoNormal\"\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eWe offer a variety of optional valve \u0026amp; spring packages for these heads. Our standard spring \u0026amp; valve package comes with GM titanium intake and Manley stainless steel exhaust valves. These are paired with a BTR dual spring kit and titanium retainers. A variety of other hardware options are available.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"MsoNormal\"\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eCall us at 815-725-2727 to discuss your requirements. Pricing is per pair. Shipping charges are not included.\u003c\/span\u003e\u003c\/p\u003e\n\u003cdiv style=\"padding: 177.78% 0 0 0; position: relative;\"\u003e\u003ciframe title=\"GM LT4 CNC Porting on 5-Axis\" style=\"position: absolute; top: 0; left: 0; width: 100%; height: 100%;\" src=\"https:\/\/player.vimeo.com\/video\/1054583051?badge=0\u0026amp;autopause=0\u0026amp;player_id=0\u0026amp;app_id=58479\"\u003e\u003c\/iframe\u003e\u003c\/div\u003e\n\u003cp class=\"MsoNormal\"\u003e \u003c\/p\u003e\n\u003cp class=\"MsoNormal\"\u003e\u003cstrong\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eNOTE \u0026amp; DISCLAIMER: GM LT heads have a known issue of dropping valves seats, particularly under extreme conditions.  While rare, any such occurrence will cause serious or irreparable damage to the engine. Borowsi Race Engines, Inc. disclaims any responsibilty for such issues as these would be GM factory defects. We offer our \u003ca href=\"https:\/\/borowskirace.com\/products\/cnc-ported-cid-6-bolt-lt-cylinder-heads-assembled?variant=46015192531156\" title=\"CNC-Ported CID, 6-Bolt, LT4 Cylinder Heads, Assembled\" rel=\"noopener\" target=\"_blank\"\u003eCID CNC-ported LT4 heads\u003c\/a\u003e as an alternative, particularly in race applications.\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003ePayment Types Accepted: Cash, Credit Card, Wire Transfer, ACH\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eBuilt by people who love motorsports for people who love motorsports\u003c\/span\u003e\u003c\/em\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003e\u003ciframe title=\"YouTube video player\" src=\"https:\/\/www.youtube.com\/embed\/Vi_TFjKdPn8?si=erUbh-PAjMoG2RZf\" height=\"315\" width=\"560\"\u003e\u003c\/iframe\u003e\u003c\/span\u003e\u003c\/em\u003e\u003c\/strong\u003e\u003c\/p\u003e","brand":"GM","offers":[{"title":"No \/ No","offer_id":46061324697812,"sku":"","price":1600.0,"currency_code":"USD","in_stock":true},{"title":"No \/ Yes","offer_id":46061324730580,"sku":"","price":2798.0,"currency_code":"USD","in_stock":true},{"title":"Yes \/ No","offer_id":46061324763348,"sku":"","price":2798.0,"currency_code":"USD","in_stock":true},{"title":"Yes \/ Yes","offer_id":46061324796116,"sku":"","price":3315.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0248\/9809\/files\/IMG_5248.jpg?v=1738958760"},{"product_id":"lt4-gm-cylinder-heads-cnc-ported-valve-guide-upgrade","title":"GM LT4 Cylinder Heads, CNC-Ported with Hardware Upgrades","description":"\u003cp class=\"MsoNormal\"\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eWe start with brand-new GM LT4 cylinder heads, disassemble them and throw out the stock springs and exhaust valves.  Our CNC-porting of GM LT heads significantly improves airflow of these heads. Our process for machining these heads starts with CNC porting on our 5-axis. This is followed by CNC valve jobbing and bowl blending in a single operation on our Newen CNC seat \u0026amp; guide machine (see video down below). \u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"MsoNormal\"\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eThe stock LT heads are known to have valve guide wear issues. We replace the factory guides with CHE valve guides made from CHE's proprietary bronze alloy. This extends the heads' longevity. \u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"MsoNormal\"\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eThe OE spring kit is replaced with a Manley NexTek dual spring kit. The new exhaust valves are Manley Extreme Duty stainless steel.  A variety of other hardware options are available on request. \u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"MsoNormal\"\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eWe know what makes power and also survives the beating of competition.  It's not chasing peak air flow at max lift by excessively cutting away the metal around the valve guides. Peak air flow occurs at only one instant in the cycle. Our focus is more on average air flow across the entire cycle. For spring packages with 0.650 inch max-lift, quoting a peak airflow at 0.800 inches is irrelevant. \u003c\/span\u003e\u003c\/p\u003e\n\u003cul\u003e\u003c\/ul\u003e\n\u003cp class=\"MsoNormal\"\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eOf paramount importance for us is that our heads don't break and wreck our engines.  We therefore do not chase flow at the expense of weakening the heads mechanical integrity. That's a concern that non-engine builders don't share.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"MsoNormal\"\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eThe air flow results we get are as shown in the Table immediately below.\u003c\/span\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003e\u003c\/span\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cdiv data-ccp-timestamp=\"1737492112015\"\u003e\n\u003cdiv data-ccp-timestamp=\"1737492112015\"\u003e\n\u003ctable style=\"border-collapse: collapse; width: 375pt;\" width=\"501\" cellspacing=\"0\" cellpadding=\"0\" border=\"0\"\u003e\n\u003ccolgroup\u003e \u003ccol style=\"mso-width-source: userset; mso-width-alt: 2338; width: 51pt;\" width=\"69\"\u003e \u003ccol style=\"mso-width-source: userset; mso-width-alt: 1621; width: 36pt;\" span=\"9\" width=\"48\"\u003e \u003c\/colgroup\u003e\n\u003ctbody\u003e\n\u003ctr style=\"height: 14.65pt;\" height=\"20\"\u003e\n\u003ctd style=\"height: 14.65pt; width: 51pt;\" width=\"69\" class=\"xl72\" height=\"20\"\u003eValve Lift:\u003c\/td\u003e\n\u003ctd style=\"border-left: none; width: 36pt;\" width=\"48\" align=\"right\" class=\"xl65\"\u003e0.1\u003c\/td\u003e\n\u003ctd style=\"width: 36pt;\" width=\"48\" align=\"right\" class=\"xl66\"\u003e0.2\u003c\/td\u003e\n\u003ctd style=\"width: 36pt;\" width=\"48\" align=\"right\" class=\"xl66\"\u003e0.3\u003c\/td\u003e\n\u003ctd style=\"width: 36pt;\" width=\"48\" align=\"right\" class=\"xl66\"\u003e0.4\u003c\/td\u003e\n\u003ctd style=\"width: 36pt;\" width=\"48\" align=\"right\" class=\"xl66\"\u003e0.5\u003c\/td\u003e\n\u003ctd style=\"width: 36pt;\" width=\"48\" align=\"right\" class=\"xl66\"\u003e0.6\u003c\/td\u003e\n\u003ctd style=\"width: 36pt;\" width=\"48\" align=\"right\" class=\"xl66\"\u003e0.7\u003c\/td\u003e\n\u003ctd style=\"width: 36pt;\" width=\"48\" align=\"right\" class=\"xl66\"\u003e0.75\u003c\/td\u003e\n\u003ctd style=\"width: 36pt;\" width=\"48\" align=\"right\" class=\"xl67\"\u003e0.8\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 15.75pt;\" height=\"21\"\u003e\n\u003ctd style=\"height: 15.75pt;\" class=\"xl73\" height=\"21\"\u003eIntake\u003c\/td\u003e\n\u003ctd style=\"border-left: none;\" align=\"right\" class=\"xl75\"\u003e91\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl68\"\u003e160\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl68\"\u003e240\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl68\"\u003e297\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl68\"\u003e335\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl68\"\u003e358\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl68\"\u003e375\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl68\"\u003e382\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl69\"\u003e382\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 16.15pt;\" height=\"22\"\u003e\n\u003ctd style=\"height: 16.15pt;\" class=\"xl74\" height=\"22\"\u003eExhaust\u003c\/td\u003e\n\u003ctd style=\"border-left: none;\" align=\"right\" class=\"xl76\"\u003e69\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl70\"\u003e126\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl70\"\u003e180\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl70\"\u003e198\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl70\"\u003e221\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl70\"\u003e236\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl70\"\u003e246\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl70\"\u003e249\u003c\/td\u003e\n\u003ctd align=\"right\" class=\"xl71\"\u003e249\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cp class=\"MsoNormal\"\u003e \u003c\/p\u003e\n\u003cdiv data-ccp-timestamp=\"1737492514444\"\u003e\n\u003ctable style=\"border-collapse: collapse; width: 148pt;\" width=\"197\" cellspacing=\"0\" cellpadding=\"0\" border=\"0\"\u003e\n\u003ccolgroup\u003e \u003ccol style=\"width: 119px;\" width=\"120\"\u003e \u003ccol style=\"width: 77px;\" width=\"77\"\u003e \u003c\/colgroup\u003e\n\u003ctbody\u003e\n\u003ctr style=\"height: 14.65pt;\" height=\"20\"\u003e\n\u003ctd style=\"height: 14.65pt; width: 90pt;\" width=\"120\" class=\"xl65\" height=\"20\"\u003eIntake Valve:\u003c\/td\u003e\n\u003ctd style=\"width: 58pt;\" width=\"77\" class=\"xl68\"\u003e2.126\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 15.75pt;\" height=\"21\"\u003e\n\u003ctd style=\"height: 15.75pt;\" class=\"xl66\" height=\"21\"\u003eExhaust Valve:\u003c\/td\u003e\n\u003ctd class=\"xl69\"\u003e1.590\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 16.15pt;\" height=\"22\"\u003e\n\u003ctd style=\"height: 16.15pt;\" class=\"xl66\" height=\"22\"\u003eAfter Intake:\u003c\/td\u003e\n\u003ctd class=\"xl69\"\u003e296cc\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 14.65pt;\" height=\"20\"\u003e\n\u003ctd style=\"height: 14.65pt;\" class=\"xl67\" height=\"20\"\u003eAfter Exhaust:\u003c\/td\u003e\n\u003ctd class=\"xl70\"\u003e110cc\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 14.65pt;\" height=\"20\"\u003e\n\u003ctd style=\"height: 14.65pt;\" class=\"xl67\" height=\"20\"\u003eMax Lift\u003c\/td\u003e\n\u003ctd class=\"xl70\"\u003e0.65\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 14.65pt;\" height=\"20\"\u003e\n\u003ctd style=\"height: 14.65pt;\" class=\"xl67\" height=\"20\"\u003eChamber Volume\u003c\/td\u003e\n\u003ctd class=\"xl70\"\u003e65.5cc\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/div\u003e\n\u003cp class=\"MsoNormal\"\u003e \u003c\/p\u003e\n\u003cp class=\"MsoNormal\"\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eCall us at 815-725-2727 to discuss your requirements. Pricing is per pair. Shipping charges are not included.\u003c\/span\u003e\u003c\/p\u003e\n\u003cdiv style=\"padding: 177.78% 0 0 0; position: relative;\"\u003e\u003ciframe src=\"https:\/\/player.vimeo.com\/video\/1054583051?badge=0\u0026amp;autopause=0\u0026amp;player_id=0\u0026amp;app_id=58479\" style=\"position: absolute; top: 0; left: 0; width: 100%; height: 100%;\" title=\"GM LT4 CNC Porting on 5-Axis\"\u003e\u003c\/iframe\u003e\u003c\/div\u003e\n\u003cp class=\"MsoNormal\"\u003e \u003c\/p\u003e\n\u003cp class=\"MsoNormal\"\u003e\u003cstrong\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eNOTE \u0026amp; DISCLAIMER: GM LT heads have a known issue of dropping valves seats, particularly under extreme conditions.  While rare, any such occurrence will cause serious or irreparable damage to the engine. Borowsi Race Engines, Inc. disclaims any responsibilty for such issues as these would be GM factory defects. We offer our \u003ca rel=\"noopener\" title=\"CNC-Ported CID, 6-Bolt, LT4 Cylinder Heads, Assembled\" href=\"https:\/\/borowskirace.com\/products\/cnc-ported-cid-6-bolt-lt-cylinder-heads-assembled?variant=46015192531156\" target=\"_blank\"\u003eCID CNC-ported LT4 heads\u003c\/a\u003e as an alternative, particularly in race applications.\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003ePayment Types Accepted: Cash, Credit Card, Wire Transfer, ACH\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003eBuilt by people who love motorsports for people who love motorsports\u003c\/span\u003e\u003c\/em\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003e\u003cspan style=\"font-size: 12.0pt; line-height: 107%;\"\u003e\u003ciframe width=\"560\" height=\"315\" src=\"https:\/\/www.youtube.com\/embed\/Vi_TFjKdPn8?si=erUbh-PAjMoG2RZf\" title=\"YouTube video player\"\u003e\u003c\/iframe\u003e\u003c\/span\u003e\u003c\/em\u003e\u003c\/strong\u003e\u003c\/p\u003e","brand":"GM","offers":[{"title":"Default Title","offer_id":46261100118228,"sku":"BRE043609","price":4995.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0248\/9809\/files\/IMG_5248.jpg?v=1738958760"}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0248\/9809\/collections\/Borowski_Cylinder_Head_Packages.jpg?v=1618766498","url":"https:\/\/borowskirace.com\/collections\/cylinder-head-packages\/aluminum+severe-duty-intake+cid+bbc.oembed","provider":"Borowski Race Engines","version":"1.0","type":"link"}