Bare; Unported; These Cylinder Heads Can Not Be Used Without Professional Head Preparation; For Use With Small Block Ford Engines; 7.3 Degree X 0.3 Degree Valve Angle; 20CC Combustion Chamber; 1.16 Inch X 1.76 Inch Intake Port Entry; 1.50 Inch X 1.36 Inch Exhaust Port Exit; Use With 2.24 Inch Intake Valves And 1.64 Inch Exhaust Valves; Hot Isostatic Pressing (HIP) Process; Aluminum; Single; Valve Seats And Valve Guides Included But Not Installed