Chalmers T 816 drive belt

I recently picked an t816.tore it down .repaired the vera shift.freed up the clutch linkage. Now I'm swapping out the 16 opposed for a 19.5 opposed.ill use the same drive pully off the 16 on the 19.5.trying to find a drive belt.front.one.problem is I'm getting all kinds of different numbers.so what have you used.tsc is where I'll get one as soon as I figure out which one.no deck.just a yard mule. Fun toy.