The Edelbrock #60759 Performer cylinder head is designed for 302, 327, 350 and 400 cid small-block Chevy engines up to 1986. This cylinder head includes your choice of 64cc (In order to retain stock compression ratio on 1970 and earlier small-blocks) or 70cc combustion chambers and high flow intake and exhaust ports. A Complete head includes larger-than-stock 1.46" valve springs to handle most high-lift cams. This head retains the stock intake port location for compatibility with standard manifolds and headers. Heat crossover is machined for 50-state emissions legal performance.