Rear tire size needed for 340 stroker?

A 275/60/15 tire on a 8 inch wheel with 41/2 inch back spacing will fit. Doesn't require any cutting or welding or spring relocation kit.
A 275/60/15 on a 7" rally wheel with 4 1/4" back spacing hit the springs on my 73 Duster with stock 8 1/4 rear end. It way fit with the 8 3/4 rear end but would hit on mine without the relocation kit. If you use a wheel with 4" or less back spacing you may be able to pull it off but then the rear wheels stick out kind of far for my liking. It`s all personal preferance i guess.