The Edelbrock #607719 Performer RPM heads are designed for use with non-emission 1968-91 Chrysler 318-340-360 c.i.d. engine applications. The Edelbrock #607719 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 FLAT TAPPET CAMSHAFT APPLICATIONS • Delivers outstanding performance in non-emission 1967-91 Chrysler 318-340-360 c.i.d. engines • Make 417 horsepower and 397 ft-lbs. of torque on pump gas with an Edelbrock Performer RPM intake manifold and matching camshaft • The special valvetrain in the 1970 340 T/A is not compatible with these cylinder heads. Match with Edelbrock head gasket sets. • Recommended spark plugs are Champion RC12YC or equivalent 14mm x 3/4" reach with flat gasket seat. • Deck thickness: 5/8" • Pushrod diameter: 5/16".