I ordered up custom 4.75 backspace rally wheels from Summit for my Dana equipped 70 Challenger to run 275-60-15's. On 8 inch wheels. Run 235's on front with 7 inch wheels.

I have one set with 275 Goodyear radials and a second set with OE type bias Goodyear Polyglass(L-60-15,,,same 28 inch diameter as 275's).

Perfect stance for me. 4.5 inch backspace gave only 1/4 inch clearance from fender lip on one side with perhaps 3/8th on other. I would never consider trimming fender lips,,,,unless I decided that self inflicted masochism was my new calling.

255's or G-60's if Goodyear Polyglass will work fine with 4.5 backspace.