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

Part Number: 12556463

ALL  CYLINDER HEAD ASSEMBLY - Part Number 12556463
Cylinder Head Assembly Corvette aluminum. An advanced-design, affordable aluminum cylinder head assembly that's ideal for street rods, fresh-water power-boats, and other high-performance applications. The head is based on Corvette L98 light alloy castings (P/N 10088113 and features D-shaped exhaust ports, high-velocity intake runners, and centrally located spark plugs. Raised rocker cover rails with machined sealing srufaces virtually eliminate valve cover gasket oil leaks. Valve seat inserts for 1.94-inch intake valves and 1.50-inch exhaust valves are installed in the 58-cc combustion chambers. Assembly includes heavy-duty valve springs P/N 12551483, intake valves P/N 12550909, exhaust valves, P/N 10241743, valve spring caps P/N 10212808, valve spring shims P/N 1255216. Both ends of the head are machined for alternator, power steering, and A/C compressor mounts. Bare casting weighs 19 pounds. Note: Exhaust port exits are 0.100-inch higher than production cast iron head, so exhaust manifolds and headers may require modifications for maximum airflow. Spark plug holes are angled. Composition head gasket with stainless steel fire rings is recommended to prevent galvanic action between aluminum head and cast iron engine block. 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.
Corvette Aluminum 1966 1967 1968 1969 1970 1971 1972 1973 1974

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