There is not alot of inside room with the leaf springs in the stock location. 4 3/4 is the optimal wheel backspacing for an 8 inch wheel. You can fit about 11 inches of section width without rubbing, maybe 11 1/4.

Any tighter will start rubbing the leaf spring in turns most likely. My slicks are about 11.6 and 28 inches tall and touch the springs on tight turns, only about 1/4 inch of clearance. If I space them out 1/8” they touch the inside of the outer wheelhouse instead. More clearance, maybe 3/8” to the wheelhouse that way (but I hate it scuffing the side wall).

This is with SS springs and regular shocks, I might be able to get away without rubbing with stiffer shocks or if the rear was higher (made in mexico SS springs sagged about 2 inches after a year or two), but if you have stock springs I’m sure it’d rub more.