The Edelbrock #61695 Performer RPM cylinder heads are designed for use with Windsor blocks including the 289-302 and 351W, allowing the creation of "Mock Boss" 302 or 351 "Clevor" Ford applications. The Edelbrock #61695 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.INSTALLATION NOTE: • EQUIPPED WITH SPRINGS FOR USE IN HYDRAULIC ROLLER CAMSHAFT APPLICATIONS • Features the desirable Boss 302 adjustable 7/16" stud and guideplate configuration • Match with Edelbrock Performer RPM E-Boss manifolds for optimum performance • Match with Edelbrock head gasket sets. • With 7/16" bolts on 289/302 engines, use Edelbrock stepped head bolt washer kit #9680. • Recommended spark plugs 14mm x 3/4" reach with flat gasket seat (Champion RC12YC). • Deck thickness: 5/8" • Rocker stud diameter: 7/16" • Pushrod diameter: 5/16" (width of slot in guide plate).