Description:

We 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 Made in USA 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. 

While 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 & 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.

The 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.

The Borowski-Manley dual LS valve spring kit includes:

• dual Manley NexTek valve springs with 1.340 in. outside diameter, 394 lbs./in. rate, and 1.050 inch Coil Bind Height,
• Manley titanium valve spring retainers - Dual, Tall Style, 7 Degree, Titanium, 1.200 in. Retainer O.D,
• Manley valve spring locators - ID: .567", OD: 1.320", Thickness: .035", Shoulder Diameter: .715",
• Manley machined bead valve locks with valve stem seals. 

If 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

You 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:

Dyno Video

Machining Videos

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