Designed for 396, 427 & 454 (7.4L) c.i.d. engines, these 100cc semi-open chamber heads feature a 1-1/2° rolled over (angle milled) design that improves intake port alignment and provides a smaller combustion chamber without shrouding the valves. The 100cc combustion chambers are coupled with the same size valves and ports as the #60459 Performer RPM heads, producing 9.2:1 compression with flat-top pistons for an outstanding high performance street head. When used on 1987-up TBI equipped 7.4L dished piston motors they produce an 8.8:1 compression ratio and made over 450 ft/lbs. torque when combined with our Multi-Point EFI System. The heads also feature an exhaust crossover passage for 50-state emission legal status. Available assembled with high quality components: one piece stainless steel, 2.19" intake and 1.88" exhaust valves: ARP 7/16" diameter rocker studs, bronze guides and ductile iron seats with 3-angle valve job. Features stock port locations, 9/16" deck thickness and heli-coils in the rocker stud and exhaust bolt holes. Mark IV rocker arms and valvetrain parts required.