Biggest Tire In Stock Wheel Well?

I have 235/60-15s mounted on cop car wheels on the Demon. They are very snug in the front wheel wells. I tried 255s out back, but went to 235 when I found they would not fit up front. They will fit, but there's very little lateral room with the springs in the stock location. You might get that large of a tire to fit under the wheel well if the leaf springs are moved inboard. I can't see how you'd be able to do it otherwise.