Cylinder Head Specifications:; Combustion chamber volume: 87cc; Intake runner volume: 215cc; Exhaust runner volume: 175cc; Intake valve diameter: 2.11"; Exhaust valve diameter: 1.66"; Valve stem diameter: 11/32"; Valve guides: Manganese bronze; Deck thickness: 5/8"; Valve spring diameter: 1.46"; Valve spring maximum lift: .575"; Rocker stud: 7/16"; Guideplate: Hardended steel; Pushrod diameter: 5/16"; Valve angle: 14°; Exhaust port location: Stock Ram Air IV; Spark plug fitment: 14mm x 3/4 reach, gasket seat. These cylinder heads are designed for outstanding performance gains in 1962-79 389-455 c.i.d. Pontiac engines. They are patterned after the 1969-70 Ram Air IV Pontiac cylinder head. Performer heads #60579/#60575 are 50-state emissions legal for 1965-79 vehicles. They feature 87cc combustion chambers designed to maximize performance while using less expensive, low-octane fuel with a streetable 9.5:1 compression ratio. Our Performer RPM heads with the 72cc combustion chamber are for higher compression engines. Performer RPM #60509 is semi-machined and must be finished by a professional cylinder head porter. They include valve guides and seats installed 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: 5/8", rocker stud diameter: 7/16", pushrod diameter: 5/16" (width of slot in guide plate).

This Part Fits:

Year	Make	Model	Submodel
1975	Buick	LeSabre	Custom
1975	Oldsmobile	98	Luxury
1975	Oldsmobile	98	Regency
1975	Oldsmobile	Custom Cruiser	Base
1975	Oldsmobile	Custom Cruiser	Panel
1975	Oldsmobile	Delta 88	Base
1975	Oldsmobile	Delta 88	Royale
1965-1978	Pontiac	Bonneville	Base
1976-1978	Pontiac	Bonneville	Brougham
1965-1970,1978	Pontiac	Bonneville	Safari
1965-1967	Pontiac	Catalina	2+2
1965-1978	Pontiac	Catalina	Base
1971-1972	Pontiac	Catalina	Brougham
1965-1978	Pontiac	Catalina	Safari
1965-1970	Pontiac	Catalina	Ventura
1967-1970	Pontiac	Executive	Base
1967-1970	Pontiac	Executive	Safari
1967-1969	Pontiac	Firebird	400
1967-1977	Pontiac	Firebird	Base
1970-1974,1976	Pontiac	Firebird	Esprit
1970-1979	Pontiac	Firebird	Formula
1967	Pontiac	Firebird	HO
1969-1979	Pontiac	Firebird	Trans Am
1973-1975	Pontiac	Grand Am	Base
1975-1977	Pontiac	Grand LeMans	Base
1975,1977	Pontiac	Grand LeMans	Safari
1965-1974,1976-1977	Pontiac	Grand Prix	Base
1975,1977	Pontiac	Grand Prix	LJ
1975-1977	Pontiac	Grand Prix	SJ
1971-1978	Pontiac	Grand Safari	Base
1971-1974	Pontiac	Grandville	Base
1975	Pontiac	Grandville	Brougham
1965-1973	Pontiac	GTO	Base
1970-1971	Pontiac	GTO	The Judge
1968-1977	Pontiac	LeMans	Base
1972-1974	Pontiac	LeMans	Luxury
1969-1970,1973-1975,1977	Pontiac	LeMans	Safari
1974	Pontiac	LeMans	Safari Luxury
1970-1977	Pontiac	LeMans	Sport
1971	Pontiac	LeMans	T37
1965-1966	Pontiac	Star Chief	Base
1966	Pontiac	Star Chief	Executive
1968-1970	Pontiac	Tempest	Base
1968-1969	Pontiac	Tempest	Custom
1970	Pontiac	Tempest	GT
1968-1969	Pontiac	Tempest	Safari