Cragar SS unilug has two appropriate options
15 X 10 (w) 4.25 BS
15 X 8 (w) 4.25 BS
1. Will 4.25 BS as opposed to 4.5 cause a conflict
2. I’d rather the 10” wide rim to get a deeper appearing dish. Will a 275 fit on it? will this cause the sidewall to relax or offset to close to the fender lip? Would the 10” outer rim/tire be to close to the fender lip?
Thanks in advance for any advice.
4.25 will not be a problem on the 8" wheel. This sets it far enough back that it will clear the fender lip and the spring. Of course there are assembly variations from car to car and if replacement quarters have ever been installed it will alter the size of the wheel lip as well, but they should fit without issue.
4.25 back space on a 10" rim will cause interference issue with the wheel lip. The 4.25 back space with 275 tire on an 8 inch rim will give you around a half inch of space to the wheel lip +/- and eighth. Sticking the wheel another 2 inchs out with a 15x10 blows this clearance away. They flat out don't fit, at all. The best way you can get that rim to fit is relocate the springs and swap the rear end to a B body unit, even then I don't think you'll get enough room.
BTW, yes, you can get a 275 on a 10 rim. It does stretch them a bit, but they will fit.
