15 x 8 Americans

i have 15x8 American racing Outlaws on the back of my '71 Dart with BFGoodrich Radial T/A 255/60-15's. the do not rub at all, but the back is raised with long shackles. i'm not sure of the backspace on the rims, but there is only 1/2 inch or so of clearance between the tires sidewall and the leaf spring. i'm taking these rims off as soon as i can find something else as i dont really care for them much. i also have a set of 14x7's from the front that i took off already.