Cylinder Head Specifications: Combustion chamber volume: 60cc; Intake runner volume: 205cc; Exhaust runner volume: 62cc; Intake valve diameter: 2. 08"; Exhaust valve diameter: 1. 60"; Valve stem diameter: 11/32"; Valve guides: Manganese Bronze; Deck thickness: 5/8"; Valve spring diameter: 1. 46"; Valve spring maximum lift: . 575"(5028) / . 650"(5027); Rocker stud: 3/8"; Guideplate: Hardened steel; Pushrod diameter: 5/16"; Valve angle: 20°; Exhaust port location: Stock; Spark plug fitment: 14mm x 3/4 reach, gasket seat INSTALLATION NOTE: Hardened pushrods required, use Edelbrock #9632 (flat tappet only) for 302 applications. Will not accept rail rockers. 289-302 V8s require Head Bolt Bushings #9680 and either Head Bolt Kit #8552 (7/16") or stock head bolts. Match with Edelbrock head gasket sets. Bare heads will have valve guides and seats installed, but will require final sizing & a valve job to match the valves you will be using. Recommended spark plugs are Champion RC12YC or equivalent 14mm x 3/4" reach with flat gasket seat.