Wheel Size for 1968 Barracuda

I run 255x60x15 on my fastback and I’m almost certain they 8” wheels from wheel vintiques. The 7” had a larger 4.25 backspacing and I just measure my front spacing quickly at 4” which would be 2.75 if I had 7”. I would be careful with the front, I have 215/60/15 on mine with no problem but previously I had 225/50/17 on all 4 corners and the front wheel cleared fender when turning. Change to disc brakes and first ride out I folded the corner of the fender, try to avoid that it’s heartbreaking. All 5x4 bolt pattern, stock A body 8 3/4 rear