Super G carburetor. Shovel, fits all engines 1966-1978 with O-ring style heads. Super G carbs have 2 1/16 inch throat and are recommended for use on a 74 c.i. and larger displacement H-D Big Twin and Sportster (not 883cc or 900cc) engines -- primarily those engines where some performance modifications such as head porting, a cam change, big bore cylinders, stroker flywheels, etc. have been done or are going to be done. Call 1-800-366-3464 for price.