15" steel rims for (4") small bolt pattern?

15x7 from wheel vintiques will have a 4.25 backspace and 15x8 is 4.5. Dart wheel wells are tight when going larger. I'm currently running 235/60/15 MT drag radials on mine. I believe that 255's will fit,but it will be close. It depends a lot on the car since they are all a little different. Have you moved the springs in with offset hangars? What modes have you done to the rear end? Minitubbed?