The Edelbrock #60839 Performer RPM Bare cylinder heads are designed for 1961-79 Chrysler 361-440 c.i.d. Wedge engine applications. The Edelbrock #60839 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. For use on pre-pollution controlled vehicles only.INSTALLATION NOTE: • Bare heads will have valve guides and seats installed, but will require final sizing and a valve job to match the valves you will be using. • Cylinder heads flow 291 cfm on the intake and 217 cfm on the exhaust at .600" lift • Angled spark plugs for superior combustion • 88cc chambers are machined .100" for clearance with quench dome style pistons • For headers, contact TTI (951) 371-4878. • Vacuum advance distributor may not clear cylinder head. • Deck thickness: 5/8" • Pushrod diameter: 3/8"