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. 9.2:1 compression with flat-top pistons for an outstanding high performance street head. 8.8:1 compression ratio when used on 1987-95 TBI-equipped 7.4L dished piston engines. Performer applications include heat crossover passage for emissions related engines. Performer 454-O are 50-state street legal.
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. 9.2:1 compression with flat-top pistons for an outstanding high performance street head. 8.8:1 compression ratio when used on 1987-95 TBI-equipped 7.4L dished piston engines. Performer applications include heat crossover passage for emissions related engines. Performer 454-O are 50-state street legal.