Welcome to Moparts! I had a '66 Coronet 440 w/ that same combo, 4.25 b/s on the front & 4.5 b/s rear, 225/70-15 on the front & 255/60-15 on the rear, no issues rubbing with no load and I had it kinds low. But if you put ANYTHING in the back seat the top edge of the rear tires would rub the outer wheelhouse. Another issue I had was I know the shocks were shot, maybe the springs too 'cause it sat so low. But that didn't bother me 'cause I did'nt drive it that much and I liked the look.