Will 275's fit?
275/60s with 15 x 8, 4.5 inch backspacing no problem on mine, perfect actually. But my axle width and spring location is not stock (fr0m to drum rear axle 58 1/4 inches from memory, and I have 1/2 inch spring relocation kit. But then again 275/60s also fitted on the previous set up where I had 4 inch backspacing on an 8 inch rim, stock spring location. My guess is that with 4 3/4 backspacing the inside of the tire would be very close to the leaf springs, if not rubbing. Simple solution would be to fit a tire and see how it goes (but Im assuming you dont yet have the 275/60s nor can borrow one).
275/60s with 15 x 8, 4.5 inch backspacing no problem on mine, perfect actually. But my axle width and spring location is not stock (fr0m to drum rear axle 58 1/4 inches from memory, and I have 1/2 inch spring relocation kit. But then again 275/60s also fitted on the previous set up where I had 4 inch backspacing on an 8 inch rim, stock spring location. My guess is that with 4 3/4 backspacing the inside of the tire would be very close to the leaf springs, if not rubbing. Simple solution would be to fit a tire and see how it goes (but Im assuming you dont yet have the 275/60s nor can borrow one).