1967 Barracuda rear tire/rim help needed

I run 275/60-15's on mine with 8 inch rims and 4 1/4 backspacing. They fit perfectly when I had small bolt pattern axles. When I switched to big bolt pattern it set the wheels a little further out and I had to roll the fender lip. 255's should fit fine width wise, but at 29 inches tall you will be close to the front edge of the wheel well, and may have to add a 1/2 inch spacer between the frame and the front spring mount to set the rear end back a bit.

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