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

275's will fit with the MP offset kit, you will not get 295's in there without a mini-tub and 3" relocation.

Do you have BBP or SBP drums? Makes a difference. With an offset kit to run 275's you'll want more like 5.5" of backspace. All you have to do is look at Unconventional's measurements, a 15x8 with 4.5" of backspace and a 245 only has 3/4" to a rolled fender lip. That means without rolling even a 245 would be pretty tight to the quarter, but there's still an inch to the springs where you only need about a 1/2". So, add a 1/2" to the backspace and now you're at 5", add another 1/2" for offset springs and now you're at 5.5" to center the wheel in the tub. And we still don't know if you've got BBP axles and brakes. If you do, you probably need even more backspace.

I think Peter's 18x9's have like 5.9" of backspace?