Manufactured in Ohio USA the CID GEN V LT1 & LT4 6 Bolt Cylinder Heads were the world’s first aftermarket GEN V LT Cylinder heads. With the CID 6, BOLT GEN V LT heads we set out to address all the underlying problems associated with factory cylinder heads when trying to increase horsepower levels.
Chasing increased HP levels requires increased airflow. This was addressed by the port design work care of Greg Good. The intake port flows 330CFM @.500” lift with almost 360CFM available @ .800” valve lift through the factory intake valve size and location, but with almost 30cc less port volume than a ported factory casting. Completely redesigned with extra material added to improve the port shape, the intake port retains a marginally smaller opening than a factory opening. The exhaust port flows a healthy 270+ CFM through the factory exhaust valve size.
Increased HP levels can require improved head clamping, so we added extra head bolts to not only create the first aftermarket GEN V LT1 head but the first GEN V LT1 head with 6 head bolts per cylinder.
A robust casting was also on the to do list, so we started with a 25% thicker deck than the factory unit. Next, the water jacket was completely revised to further strengthen the casting, allowing heavier and larger diameter springs, increased rigidity for higher chamber cylinder pressure control, along with increased material around the already modified intake and exhaust ports, that allow for port modifications not possible within a factory casting. Then we cross braised the rocker stands by tying them together with one continuous rocker stand bar that runs the length of the cylinder head, allowing the use of an aftermarket shaft mounted rocker system if required. All heads come with CHE precision bronze valve guides and CHE iron valve seat inserts.
Heads come machined to accept LT1 and LT4 intake bolt holes, are available with either Factory style LT1 or LT4 CNC chambers, as well as Greg Good developed CNC chamber that is the same CC's as a LT1 chamber, and will accept all factory rocker gear, valves and springs.
Heads come CNC ported with bare heads starting at $3300 including CNC chambers and valve job. All sales are outright and do not require the return of the factory castings.
Bigger isn't always better when it comes to cylinder heads, and proof came in the way of a almost 60 RWHP gain over factory heads on a cam swap only Standard Bottom End. Compression was increased 1 point with the head swap and the car was the first known to exceed 600 RWHP with a SBE Cam and head swap only.
Before and after head swap graph below.
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