rear tires not centered in body

Dang, tonight I tried some 15x7 (4.25 backspace) Rallys with 255-60/15's. The right side had plenty of clearance inside and out but the drivers side was quite tight. (barely a finger width on the inside and outside.) I hope I don't ruin a tire but it could happen. I imagine the quarter was fixed before paint and I would estimate the tub is a inch smaller on the drivers side.044.jpg