1966 1967 1968 1969 1970 1971 1972 1973 1974 ALL BOWTIE HEAD ASSEMBLY

Part Number: 25534431

ALL  BOWTIE HEAD ASSEMBLY - Part Number 25534431
Bowtie Head Assembly Large Port Vortec . GM performance parts most powerful cast iron cylinder head for street or racing applications features revised intake and exhaust ports and includes 2.15-inch stainless intake valves P/N 25534407 and 1.55-inch stainless exhaust valves P/N 25534408. Deck surface thickness is 0.450-inch with 66-cc combustion chambers, 185-cc intake and 84-cc exhaust ports. All Vortec intake ports are taller and narrower than early model Chevrolet heads. Valve cover mounting hole accommodate both early perimeter-style and newer center-bolt mount. Intake mounting holes accommodate early six-bolt and newer four-bolt Vortec-design intakes. Head includes screw-in rocker studs P/N 12552126 and large valve pocket machining. It will accept up to .530-inch-lift camshafts without modifications. Head assembly includes valve springs P/N 1551483, valve seals P/N 10212810, and spring caps P/N 10212808. Designed for high-horsepower and high -rpm applications. Note: Must use raised runner design intake manifold (six-bolt style) or Vortec design (four-bolt style). Use with Vortec intake gaskets P/N 12529094 or dual-pattern intake gaskets P/N 12497760 for early model raised runner or Vortec intake manifolds. GM Performance Parts cylinder heads are created with GM premium-engineering, then cast and machined to our exacting manufacturing standards. GMPP cylinder heads are available as bare castings or complete cylinder head from service replacement castings to all-out competition applications.
Large Port Vortec 1966 1967 1968 1969 1970 1971 1972 1973 1974

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