Quote: rear fenderwell clearance: these are perfectly squared up with equal clearance on inside and out. rims have 4-1/4" bs.
Thanks for that Gary (and for all the pics). So the trade off would be whether to run with the 15x7 @ 4" BS or the 15x8 with the 4.5" BS. Either way, a 255 tire should fit (at least, it looks like it will).
If everyone is measuring backspace the same - the bigger 255 tire on a 8" wheel would be 3/4"+ closer to the wheel lip.
I don't think there's room for that.