I ran 245/60/15 on weld 7" rim with 4.5 backspace... I also ran the 245/60/15 on a 7" wide 4.25 backspace cop rim off a mid 80s dippy on the rear of my 68 Dart.

I had a-body 8 3/4 housing with large brake offset axles. this makes the stock a-body small brake offset axle 8 3/4 a 1/2" wider (1/4" each side)

the 4.5 offset on the 7" wide rim with 245/60/15 tire put it in the center of the stock 68 wheel well tub.