belts use the part # in relation to the length so like I have a gates green stripe TR0426 on my '51 chevy which is 5/8" wide and 43" long, if I got a TR0427 or maby 0428 might be 1/2" or so longer even tho I just checked gates site and they are not listed as existing, it was an example. any good parts store will be able to figure this out and get you what you need.