The Edelbrock part # 77419 Victor 24° 340cc cylinder head features a rolled over deck, altered valve locations and partially CNC'd 199cc chambers for cost effective performance. The Edelbrock 77419 cylinder head comes bare and will need a final valve job and guide sizing before use. The 340cc rectangle ports produce impressive flow and great power on competition big-blocks with 4.470" or larger bore. Exhaust port exits are raised .534". INSTALLATION NOTE: Matching stud girdle #7796 must be used with stud mounted rocker arms. Deck thickness: 9/16", rocker stud diameter: 7/16", pushrod diameter: 3/8" (width of slot in guide plate).