For 1972-73 Mercury Cougars and Ford Mustangs with the 351W engine. This is a Pitts manufactured pulley and clutch assembly with a pulley diameter of 6-5/16", a clutch diameter of 5-1/8", and an overall thickness of 1-11/16 inches. Whew boy, say that 5 times fast!
Ford part # D2ZA-2981-A. May also have part numbers of D2ZA-2981-A1A, D2ZA-2981-A1B, or D2ZA-2981-A2A.