you need a 5 x 4.5 bolt pattern ( 5 x 114.3 in metric), but i dont know if there will be any clearance issues with the wheel openings - others here can advise on that
Well all I can tell you is on my 69 Fury III on the rear I run 15/8 wheels with 4 1/2 back spacing with 275/60/15. They fit fine. But I don't think that will help you.
Check the threads. Don't go to a garage without telling these beasts with an impact wrench that the drivers side is reverse threads. They could snap them off. Both reverse threads are on the drivers side.