The Victor 24° features a rolled over deck, altered valve locations and partially CNC'd chambers for cost effective performance. Complete cylinder heads offer your choice of spring packages to suite hydraulic or mechanical camshafts. Hydraulic spring package for flat tappet or hydraulic roller cams up to .700" lift available. Mechanical roller cam spec include Manley dual-spring valve springs & titanium retainers good for up to .880" lift. 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". #77439 is a great option for custom porting - seats and guides are included but not installed and the chambers are left unmachined. 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).