old tiller on newer machine.

[Hallas 0]

Im trying make an older tiller (60's?) work on my 1988 gt1142. It has the old style belt pulley that mounts on the rear tranny bracket. To get that to work the footrest would come off and it might rub a bit. I'm going to put the correct attachomatic pulley. Should use the belt that my machine calls for or is it a craphoot if the tiller dimensions are different for the older tiller. At $50+ i dont want to screw it up.