This is a brand new set of GM CNC LS9 cylinder. Uses GM LS3 valvetrain for the rockers or a aftermarket replacement. Del West titanium Intake valves and sodium filled exhaust valves. CNC Intake and Exhaust runners. Includes lash caps for the intake valves. Chevrolet Performance LS9 CNC-ported cylinder heads represent a new benchmark in factory engineering high performance, blending the strength and durability of the production LS9 cylinder head castings with the airflow enhancements of precision CNC porting. The result is about 10 percent more efficiency than the production casting, while delivering the greater strength built into the LS9--Rotocast from super-strong A356T6 aluminum alloy. With the Rotocasting method, the…