[eastonct124]

I had a heck of a time finding a replacement belt for my 1A. As far as I know, the long belt, as with the gen/starter belt, is cub only because of the deep V design.
I had to go to my local cub dealer, and even then, it was special order.
As far as the bolts go, almost every bolt is a 3/8-16. The bolts used to hold the gearbox on are 1" long. When I take the box off, I double the washers up so the bolts don't bottom out.
That's good that the tiller you bought has the extensions and covers.
Before you use it, you'll want to slide the tines off, clean up the shaft, and grease them. The pins on mine were so worn, it took awhile. I found this out while using it, and getting it apart while it was covered in dirt, in the field was a nightmare.