Specifications for the cylinder head include: combustion chamber volume of 87cc; intake runner volume of 215cc; exhaust runner volume of 175cc; intake valve diameter of 2.
11"; exhaust valve diameter of 1.
66"; valve stem diameter of 11/32"; valve guides made of manganese bronze; deck thickness of 5/8"; valve spring diameter of 1.
46"; maximum lift for valve spring is .
575"; rocker stud measures 7/16"; guide plate is made of hardened steel; pushrod diameter is 5/16"; valve angle is 14°; exhaust port location is stock Ram Air IV; spark plug fitment is 14mm x 3/4 reach, gasket seat.
Designed for performance gains in 1962-79 389-455 c.
I.
d.
Pontiac engines, these cylinder heads are patterned after the 1969-70 Ram Air IV Pontiac cylinder head.
Performer heads #60579/#60575 are emissions legal for 1965-79 vehicles in all 50 states.
They feature combustion chambers of 87cc designed to maximize performance while using low-octane fuel with a streetable 9.
5: 1 compression ratio.
Performer RPM heads with 72cc combustion chambers are for higher compression engines.
Performer RPM #60509 is semi-machined and requires finishing by a professional cylinder head porter.
They include installed valve guides and seats with no intake pushrod holes.
Performer RPM #60587 is not port matched or bowl blended and is NHRA accepted for Stock & Super Stock.
INSTALLATION NOTE: These heads require Ram Air IV (round port) style exhaust manifolds or headers and Edelbrock head bolt kit #8549.
Deck thickness is 5/8", rocker stud diameter is 7/16", and pushrod diameter is 5/16" (width of slot in guide plate).
