I just bought a 68 Charger and would like to do the nascar look with aluminum slots. I'm kind of looking for a tall wide front tire plus since I'm using 15"'s for rims I would like to know the best backspacing. I'm think that my backspacing in the rear will about 3 3/4 to 4" with 15x8.5" with 315/60/15's but I'm not sure about the front?