15x8 with a 4.5 backspace is the only way to go.You will not be able to run fender skirts IIRC.I thin I ran 255/70 on an 8" on my 68 300 years ago but I can't remember. 255/60 on a 7" rim would be safer and easier to finesse in/out of the wheel well.
Joined: Wed Dec 21 2005, 07:34AM
Location: indiana
Posts: 791
I have 275/60-15 on 15x8" Ramcharger wheels on the back of my 68 Fury. The wheels have the same BS as the factory 15x7 wheels, around 4.25" IIRC. So the extra 1" of rim goes toward the fenderskirt, and sadly, the tire bulge is right by the latch handle, and tire rotation when going forward is such that if the tire snags it it'll pop the latch open. Far uglier than losing a wheelcover. (that one's not a DAMHIK, for age and wisdom, which are the result of youthful mistakes, identified that potential problem)
So I put a slightly-narrower (about 3/4" per side?) B-body rearend under it and installed offset spring hangers/shackles also (mostly due to where the rearend's perches were, IIRC). I did all of this because I had the rims, and a buddy had all the other stuff (including 2 brand-new tires) -- and he cut me a helluva deal and did most of the work. I would not have gone thru all of that otherwise.
And whenever fitting wides on the rear of the car, always check for clearance everywhere, not just at the wheel lip. 65 and 68 Fury (probably some other slabs also) have a big rolled area in the rear wheelhouse, about 3-4" above the wheel lip, and a tire can rub it too. See the blue line for where to look. Chrysler and Plymouths sometimes have very different sheetmetal around the fenderskirts (65-66 for sure), so always check *your* car -- don't assume all C's are the same when it comes to tire clearance.
If putting tires on the front of a car, watch for clearance to everything at full turning and full jounce and rebound (easier said than done). Watch the brake hoses especially. 235/60-15 on the front of an 80 'Doba can rub thru the brake hose (that one is a youthful DAMHIK ).
So, for the rear of the car - If you have the right BS, 275 will fit. I don't know if typically-available BS will get you there, though. If you want to play it safer, go 255. 255/60-15 on a 15x7 copcar wheel (~4.25 BS) has fit perfectly for me on the rear of: 77 & 80 Cordoba, 65 & 68 Fury (with skirts) and 70 Fury (non-skirted). Should work equally as well on a 'standard BS' 15x8 wheel, and based on the wear pattern of 40k miles on a 255 on a 15x7, I 'd say an 8" rim fits a 255 better.