Alternator Belt

Does anybody know the right P/N for the alternator belt on a narrow deck O320 with the Interav? Also where did you find it? And while we're on the subject, what are your feelings about tying an extra belt around the case so you can do a quick replacement in the field without pulling the prop and nose bowl?

I need an to know this too. I have a 94 and the part No. called out by lycoming is incorrect or at least it appears that way. Bought the one they said and way to big. I need the 3/8 inch wide by 32.5 I think Anybody know for certain which belt goes here? Lycoming part No.