The Edelbrock #60517 Performer RPM NHRA Stock/Super Stock cylinder heads are designed for 1965-76 Oldsmobile 400, 425 &455 c.i.d. V8 applications. The Edelbrock #60517 Performer RPM heads are perfect for street performance, daily drivers, street rods and muscle cars where seat-of-the-pants performance is needed. These cylinder heads deliver great throttle response and power from 1500 to 6500 rpm. They also feature the highest quality intake and exhaust valves and valve springs. For use on pre-pollution controlled vehicles only.