I will be buying tires soon for my 69 Camaro, and I think my back spacing on the rallye wheels is 4.5". My question is will 275/60/15 fit on the rear with that amount of back spacing. Your help is appreciated.

yes , they fit w/o any problems

I had 265/50/15 tires mounted on 15x8 Centerlines with 4.5 inch backspacing and my tires rubbed when I turned into my driveway (which wasn't very steep). Air shocks helped to solve the problem.

I currently run 16x8 Wheel Vintiques rallys with 245/50/16 and have had no problems, even with my current steep driveway.