This head is identical to P/N 12363399, except it has 2.25" stainless steel intake valves, and 1.88" stainless steel exhaust valves with 11/32" stems.This head is used on G.M's 502/502 h.p. crate engine.
Large oval port design, 290cc runner volume , Semi Open Combustion Chamber.
It also includes high performance valve springs, valve spring caps, keys and valve stem seals.These springs are good for up to .680". Spring pressure closed is 140 lbs. Spring pressure open is 368 lbs.
These heads are designed for high horsepower 396, 427, 454, and 502 engines.
Technical Note: For 502ci engines, use head gasket kit P/N 12363411 and no sealant on the head bolt. For all big-block engines, use intake manifold gasket kit P/N 12366985, with intake bolt kit P/N 12367959, and cylinder head bolt kit P/N 12367779.Casting number for this cylinder head is 12363391.