I dont have those exact wheels but as far as backspacing on the rear wheels go, I have 15x8's 5.5bs 255/60/15 and they fit, kinda close to the springs but they work. rear end is from a 68 coronet.
For the front i'm running 15x7s and I believe they have 4.5 bs..the 18x8s with 4.5bs might stick...