Biggest tire in 64 barracuda stock configuration

I was able to get 245/60/15 on a 7" rim with 4.5" backspace on the rear of one of my cars that left 3/8" to the springs and 3/8" to the fenderwell but when I tried those same wheels and tires on an another of my cars the tire rubbed the outer fenderwell. Both 64 Barracudas, both 7-1/4 axles, same ride height on both.
I have since put an 8-3/4 in the car that rubbed with the Dr. Diff spring relocation and have 245/60R15 on 8" rims with 0 offset.

I have 205/60R15 on the front of both cars but have the 73 up disk setups on them so they are a tiny bit wider than original.