Edelbrock and Pat Musi Performance have combined efforts to produce the finest standard intake port location big-block Chevy head available. These cylinder heads feature an extra thick deck and extra material in the spring pockets for a heavy-duty casting that can be used with high-lift cam and heavy spring combinations. Edelbrock equips the complete cylinder heads with Manley dual-spring valve springs and titanium retainers good for up to .880 lift. The port designs are large oval (367 lh / 377 rh) that produce impressive flow - out-of-the-box. The exhaust port exits are raised .750 to greatly improve exhaust flow and power. Off the shelf large oval-port intakes are available through Edelbrock. INSTALLATION NOTE: Bare heads will have valve guides & seats installed, but will require final sizing & a valve job to match the valves you will be using. Deck thickness: 9/16", rocker stud diameter: 7/16", pushrod diameter: 3/8" (width of slot in guide plate).