The Edelbrock #60879 Corvette center bolt cylinder head is designed for 1986-91 Tuned Port Injected (T.P.I) 5.7L small-block Chevy Corvette engines originally equipped with center bolt valve covers. Performer center bolt cylinder heads are 50-state street legal and accept factory center bolt valve covers. The intake bolt pattern utilizes the 1986-91 (straight) 90° angle on all bolts. Spark plugs are angled like stock O.E. heads. The Edelbrock Performer heads are perfect for street performance, daily drivers, street rods and muscle cars where seat-of-the-pants performance is needed. They also feature the highest quality intake and exhaust valves and valve springs.