If you want the wheel centered in the wheeltub, it takes about 8.8" backspace which may be tough to find. That backspace is from rim edge (+.5" each side), not bead.
A stock A body 8.75 rear with BBP conversion uses ~7.75" backspace 10" rim to get them under the car.
I have 10 inch wheel with 7.5 BS 295/50/15 tires on mine. The rear tires rub on the lip of the wheel well. Probably have 2-3 inches of space to the leaf spring though. B Body rear end also.
Here you go I will try to take some from under the car if I get a chance.
Yes spring relocation kit 3" kit to the frame rails.