The SB Chevy Aluminum LT4 Cylinder Head from GM Performance Parts is a great choice for upgrading an LT1 engine. Bolt these on for an easy 25 horsepower increase. The raised intake runners require the use of an LT4 intake manifold to match the raised intake ports.
Supplied with 3/8" rocker studs for use with most common SBC rocker arms; GM factory built engines used a unique 10mm stud with non-adjustable roller rockers.
We also offer a fully CNC ported version (#SD3287) for increased airflow and more HP! Call our tech department for complete details on how to make your LT engine a street sleeper with over 400-hp!
Stock LT4 cylinder heads flow approximatley 235-cfm at 0.500" intake lift and the exhaust port flows 161-cfm at the same lift. Stock combustion chambers are 56cc's.
GM Performance LT4 heads are assembled with lightweight hollow-stem 2.000" intake valves and 1.550" sodium filled exhaust valves. Maximum vlave lift with the LT4 vlave springs is 0.525"