This GM Performance / DRCE2 Cylinder head was designed specifically for the DRCE2 block P/N 24502572. It is intended for professional competition applications. It is designed to comply with NHRA Pro-Stock rules for 500 cu. in. engines with 4.900" cylinder bore spacing. The DRCE2 heat treated head casting is sold as P/N 24502585 or as a semi-finished "cube" with bolt holes as P/N 12480010. Special DRCE2 cylinder head features include: High capacity water jacket that is self purging, symmetrical port layout with ample wall material for custom porting designs, thick deck (.850) surface without cast-in combustion chambers to facilitate "angle milling" without weakening the deck. Reduced weight casting to minimize CNC machine time. The DRCE2 cylinder head casting is produced from 357-T6 aluminum with provisions for intake valve angles of 10-14 degrees and canted 5 degrees. The exhaust valve angles of 9-5 degrees with a 2.5 degree cant. The casting is "robust" to provide adequate cylinder head clamping. A typical CNC prepared cylinder head without valves and valve train has a weight of 40 lbs. This DRCE two-head requires aluminum die cast valve cover P/N 12370852.