15x7 cragars on the front of a 69 dart?

I had a set of Cragar SS 16 X 8s on the front of a 71 Duster with the 73up discs. Picture attached
I believe the backspace was 4.5". That would put the outer bead at the same distance out as a 7" with 3.5"bs.
The difference I see is the Duster wheelwell flares out a bit where the Dart doesn't. If I had to gamble I'd be sure to get closer to 4.5" backspacing.