Repairs NEED BELT SIZE

[PAPA06]

HI TO ALL, NEED SOME HELP PLEASE TO FIND A BELT SIZE, MTD (1987) 30" cut, model 137-504-000. called mtd tech support (45 minutes) they cant supply info on blade drive (deck) belt. none of the sites i've been to show a bit of info. I think its a 52" x 1/2 " belt 754/954-0264. I put one on and it worked fine for 3 cuttings then it shredded. I got this mower for free, and was missing belt at that time, so not sure of routing. But it seems real slack until you engage drive, makes a lot of noise till then. Any ideas or assistance would be appreciated. bob