The Edelbrock #60179 Performer RPM heads are designed for use with non-emission 1968-73 Chrysler 340 c.i.d. engine applications. The Edelbrock #60179 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 • Designed for non-emission 1968-73 340 c.i.d. Chryslers, RPM Chrysler 340 cylinder heads have chambers machined .060" for clearance with early high-compression 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".