18" wheels
So, since I've sort of done this already with my car. I got 18 x 9" wheels to fit in the stock '68 Dart wheel wells with a tad bit of rubbing on all 4 corners. I used a stock A-body 8 3/4 and Dr Diff's rear disc brake. Unfortunately I needed two different offset wheels, but now that I think of it, most performance tires are directional anyway so they'll look stupid if rotated. With the 18 x 9" wheels and 255/40/18 tires, I was able to get the front to clear with no problem (I cut out the inner quarter panel supports) and the rears were tricky as my rear end was offset to one side over the other. So, we're just going to roll the fenders. I have a set of MP offset shackles (0.75") that will help me put 275's under there with no problem. I might do a wheel change, but it would be with something I like a little more visually and is lighter.