217501 - This clutch has the lip on the back of the fixed face for models where crankshaft oil seal rides on clutch lip. 1-1/4 belt width can be shimmed to 1-3/8 . 1/2 x 7-1/4 mounting bolt supplied 217506 - This clutch comes set up for 1-1/4 belt width. 1/2 x 7-1/4 mounting bolt supplied.