Muscle Head Stage III: “Big Valve” Muscle Head: Program #01, 2.600″ x 1.925″ valve dia. 99.5cc chambers. Std Copper intake valve seats, B5 Exhaust valve seats, .017″ Jr Hoops & All 9/16″ Head stud inserts. (pair)

Muscle Head Stage V: Program V3-P3-F12, 2.400″ x 1.900″ Valve dia, 102cc chambers. Std Copper intake valve seats, B5 Exhaust valve seats, .025″ Jr Hoops, 5/8″ Top Row & 9/16″ Bottom Row Head stud inserts. 2.600″ lifter spread, 12ø Exhaust Flange. (pr)