235/60's on a 7" wheel would probably fit. The 7" wheel would probably be as narrow as you would want to go with 235/60's. Backspacing should be crucial but with 4 1/2" it should be right. Do you have BBP axles installed to run the cop car rims? It its a B Body rear under an A body the backspace isn't enough on any steel wheel to get it to fit right. I tried to put a 65 B Body (narrowest one)under my 69 dart. No steel wheels I could ever find had enough backspace to use without making custom backspaced ones.