Tire/wheel sizing issues

You could probably get a b-body or c-body 8 3/4 rear cheap and have it cut down to your measurements. Then sell the a-body rear for what you have into the modified rear.

On my D/Dart, I have M/T ET Drags that are 28.0/9.0-15's mounted on 15x6 rims. The rims might have a 3.5 bs (measured from the outside edge of the bead to the mounting surface) on them. With this tire and rim setup, the tire sidewall balloons out a bit. But that's what you have to put up with when you buy used stuff. Mine only cost me $125 at a swap meet. If I had the room, which I don't, I'd go with another 1/2 backspace on mine to clear the inner fender.

I have SS springs that are located in the stock position, so it sits high. The passenger side is where I ran into a problem with the forward leaf spring clamp contacting the inside sidewall of the tire. I used a 0.190" spacer to help clear the clamp. The top is close to the inner fender but seems to be far enough away where it wouldn't hit at launch. Almost like yours.

Alan