73-76 A-Body Offset

Max rim backspacing is 4.5" with stock upper control arms. With tubular A-arms you might be able to get 4.75" because they don't have a lip on the outside edge next to the rim.

The more backspace you can run on a 15" rim will give you more room for wider tires and rims in the front of an A-body. Typical setup for a 73-76 duster would be 15x7 4.25 backspacing rims with 215/60/15 tires. Many people run 225/60/15 tires and of course they will be closer to fender fitment. Alignment. and past vehicle repair can change clearances.

The offset calculation will vary on the rim width.

I've read that the 73-76 discs will push the rims out some. Don't remember the exact amount or if someone has truly made an accurate measurement of that.