Backspacing question

Quick question: what about a 15x8 wheel with 4.5" backspacing with a 9.5 tire? Anyone see any potential issues with that as far as width issues? As you can see im a newb when it comes to this stuff. Thanks!
It wouldn't fit on my '69 GTS. Absolute max is a 235 tire which is about 9.25" depending on what wheel you use. I'd say try 15x7 with 4 1/2 BS, you may need some 1/8" or 1/4" spacers to fine-tune it. Of course it also depends on how high the rear end is sitting. The other thing that truly sucks is that both sides of these cars are seldom the same!