I got this off of nicoclub.com
Originally Posted by hurddawg
take your gates part number to any parts store they will get you the proper belt.
I did this at my local place and they gave me Dayco belts and they worked fine. The guy told me that part numbers for belts are standardized. So they can cross-reference them easily.
K050370 Alt
K040345 P/S
K 05 0370....05 indicates # of ribs, 0370 indicates length of the belt. K signifies its made my Gates.
so that implies that you can take that number to a parts store and they can hook you up with the right belt.