Bare; Unported; These Cylinder Heads Can Not Be Used Without Professional Head Preparation; For Use With Small Block Ford Engines; 11.3 Degree Valve Angle; 24CC Combustion Chamber; 1.34 Inch X 1.77 Inch Intake Port Entry; 1.66 Inch X 1.43 Inch Exhaust Port Exit; Use With 2.24 Inch Intake Valves And 1.64 Inch Exhaust Valves; 1.930 Inch Valve Spacing; Hot Isostatic Pressing (HIP) Process; Aluminum; Single; Valve Seats And Valve Guides Included But Not Installed