1993-1994 Melex 512G Needs Drive Belt

[MD2020]

Hey all, new here. I got a Melex 512g for free not too long ago. It had been sitting in a parking garage unused for over 14 years. I rebuilt the carb, dumped the old gas and she fired right up. Runs good. EVERY part on this cart is stock, so I know it saw little use.
I rebuilt the clutch and was able to find a replacement drive belt for the old Salsbury. Problem is the new belt is too tight (cart roll-starts, hard to shift gears etc.)
Does anybody here know exactly which belt will work?

The cart has the 9hp briggs vanguard and the Salsbury (780 series?? not sure) clutch.
The belt that was on it when I got it was a Salsbury Aramid Kevlar reinforced belt # 704094. The replacement I got was supposed to be an exact replacement from comet. belt model# 300661.

I'd be much obliged if someone has the same cart and can tell me which belt they have. If they weren't so **** expensive I'd just order a few different ones.

Thank you!!