I have an old Montgomery Ward tiller and I need to know belt size and configuration of the rear belt that runs the reverse. Model # is GIL 1580E S# 47-56447
According to my manual for Gilson 1580F the forward belt is 1/2 x 35, and the reverse belt is 3/8 x 37.
The reverse belt gets a 1/2 twist to reverse direction. Hard to explain, but the drawing in the manual is pretty clear.