Mini tub Dart wheel sizes

I had exactly the same 48 1/2 inches for an 8 3/4 in my 69 Dart which was mini tubbed with the springs relocated. I used 10 inch wheels with 325x50-15 tires 3.5 inch backspace. I found that 48 1/2 in my car caused the outside u - bolt to be up on the housing end almost on top of the weld. So when i changed to a Dana I made it slightly winder like 49. I now have 315x55-15 with plenty of room but had to move the wheel opening forward an inch.