Hi Calvin74, my understanding is that you will need to match the inner clutch half to the output shaft of the engine. So if you're current output shaft is 5/8" and you switch to a 3/4" shaft, you'll need to buy a 3/4" clutch half to suit. If the new 3/4" shaft engine and clutch half is cheaper than a 5/8" shaft engine on it's own, it'll be a good way to go. There's no extra labour involved as the clutch has to be removed from the engine either way. Hope this helps.
Cheers, Michael
