Some of you guys are still talking about backspacing. That does NOT matter if you are doing a custom width rear. A 10" wheel is a 10" wheel. It fits or it doesn't. So order what you want and fit the rear.

Now, that said, you can get a 10" wheel on a 63 without mini-tubs. If I mini-tubbed it, I would put a 12" wheel on it, depending on the tire you want to use

Monte