Designed for 1965-79 389-455 c.i.d. Pontiac engines, these heads are patterned after the 1969-70 Ram Air IV Pontiac cylinder head. Two styles are available: a street legal 87cc combustion chamber version for low compression applications using 92 octane fuel and a 72cc chamber version for higher compression, racing applications. Both heads have Ram Air IV exhaust port flanges.

Performer RPM Pontiac heads produce outstanding horsepower with excellent low speed torque and throttle response. High flow D-shaped exhaust ports require Ram Air IV headers or exhaust manifolds. Performer RPM heads #6057 are 50-state street legal for 1965-79 vehicles (E.O. #D-215-16). The 87cc combustion chamber has been designed to maximize combustion efficiency with streetable compression ratios such as 9.5:1. A semi-machined version of the 72cc chamber head is available for custom applications. Designed to be finished by professional cylinder head porters, this version comes with valve guides and seats installed, but with no port machine work or intake pushrod holes.

Complete heads are assembled with stainless steel, one-piece swirl-polished 2.11" intake and 1.66" exhaust valves with under-cut stems to promote excellent flow for more power. They also include 2-ring positive oil control seals, rocker studs and guideplates, valve springs, steel retainers and keepers. Both versions include bronze guides, hardened valve seats and the deck surface is 5/8" thick for superior durability and head gasket retention. All factory accessory bosses are included for bolt-on convenience.