Latest tire 1970 Swinger with mopar off set shackles can I fit a 275 tire?

I hate starting a new thread read about 15-20 pages and not clear so I have a 1970 Swinger with an 8 3/4 drum axle. I picked up a mopar off set shackles kit from a guy. I'd like to know can I tuck a 15x8 I'm guessing right now 4.5 backspace until I measure it in the wheel well with out jacking up the rear end? I'd rather not cut the wheel well but if I have to then I'd like to know will a 295 tire then fit and would a 15x10 with a 5" backspace fit or would it rub the springs? Thanks in advance.