EDELBROCK #60459 PERFORMER RPM O-PORT CYLINDER HEAD FOR BIG-BLOCK CHEVY. The Edelbrock #60459 Performer RPM O-Port cylinder head is designed for Big-Block Chevy applications. The Edelbrock #60459 Performer RPM head is perfect for street performance, daily drivers, street rods and muscle cars where seat-of-the-pants performance is needed. This cylinder head delivers 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. Exhaust 45 deg/Intake 45 deg. EQUIPPED WITH SPRINGS FOR USE IN HYDRAULIC FLAT TAPPET CAMSHAFT APPLICATIONS. Match with Edelbrock head gasket sets. Recommended spark plugs are Champion RC12YC or…