Description:
Our 427ci mechanical-roller, iron LS long blocks come in two primary flavors: conventional or copper head gaskets. This build uses Cometic MLX gaskets which have a max boost rating of 35 psi. Copper head gaskets with fuel hoops will hold far more pressure, but may require occasional torque adjustments. Those long blocks have a different part selection to better work with the higher boost levels. The top of our LS horsepower ladder is the 462ci billet aluminum long block.
This long block is intended for Drag & Drive running gasoline on the street and either gasoline or alcohol on the track. The mechanical cam enables higher rpms and higher valve lift for more air flow. That means more horsepower. The mechanical roller lifters are less prone to failure than their hydraulic roller counterparts. One trade-off is that valve lash needs to be checked regularly. The adjustments are far less frequent than in years past thanks to improvements in valve train materials and design.
We use Dart SHP blocks and incorporate three major upgrades as part of our precision CNC block machining process. The first is going from 7/16 to 1/2 inch head studs. This greatly increases clamping force on the heads. Second is replacing the main bolts with main studs. The third is machining the lifter bores to 0.904" from the stock dimension of 0.842". The larger lifters are far more reliable at higher horsepower levels.
The rotating assembly starts with a 4.000" stroke, Callies Apex center counterweighted crankshaft paired with Ultra Enforcer I-beam connecting rods. Riding on the rods are 4.125" Diamond Race Series LS dish pistons. This combination yields a 427 cubic inch displacement.
On top are our BRE-machined All Pro cylinder heads filled with the parts you need to push this engine to the limit. We start with raw castings so the ports, runners and combustion chamber are all custom. While we prefer LS7 ports, we can machine LS3 ports into the heads if that's what you need for your existing intake manifold. The port work does not change the valve angle which will remain at 12 degrees on the LS3 variant. The All Pro's are assembled with Inconel exhaust valves and Severe Duty Manley intake valves. The Manley NexTex spring kit has a coil bind rating of 0.960" allowing high valve lift.
The Jesel 1.7:1 shaft rockers stabilize the valve train at high rpms and allow easy valve lash adjustments. The mechanical roller lifters feature needleless bronze roller bearings.
Some of the other key features of this long block are:
- Callico coated Clevite bearings
- Billet double chain timing set
- Manton pushrods with upgraded tips
Drag & Drive cars put on a lot of both road miles and track passes. We offer two upgrades for enhanced longevity. First is upgrading the Jesel rockers from aluminum to stainless steel. The second is switching from bronze roller bearings in the lifters to DLC-coated steel (diamond-like carbon). These changes reduce wear which in turn reduces the need for valve lash adjustments. You can request either or both upgrades. See more about the lifter options in the video down below.
We strive to keep the required components in stock and the lead times short. This is a long block used on a lot of our builds so it is often on the floor and available for immediate shipment.
This is the long block that powered Rob Carter (Bereyt Racing) to 1st Place Street Eliminator finishes for both the FIA European and his home UK Nationals (see Note 3). He was running with conventional (Cometic MLX) head gaskets at 35 psi boost (max rating). Check out the video for more details.
A key factor in why are racers win is the high level of precision characteristic of our CNCs as can be seen in the video below:
The additional videos below will give you additional information about the key parts (All Pro heads, Callies 8-cwt cranks, Dart block and Manton pushrods). We think you'll be as convinced as we are that this long block is best in class for this power range.
Please give us a call to ask questions, price some custom options or get one started. 815-725-2727.
Notes:
- These long blocks are not polluton controlled and may not be legal for transportation in your vehicle.
- Photoset includes pictures of completed engines for illustrative purposes only. The addititional parts are not included.
- Rob's long block used an SHP Pro block. These are no longer available.
Accepted methods of payment: Cash, money order, wire transfer, ACH
