IIRC there were 4 grooves like. but it only seem to fit one way. i remember the teeth were more meatier then the stock. but i think there was 1 slot bigger then the other for the keyway on the crankshaft to enter.. because i remember now we thought the sprocket was to small for the crankshaft because we had a hard time getting it to fit. but IIRC there was only 1 way of it really going