lI've been researching this topic for a while & am still confused. I have '68 Cuda I want to put 15X8 Rallye wheels in the back. I have a 5X4 bolt pattern & stock springs. The only wheel I can find in this size has a 4-5/8" backspace from Vintiques or Coker. I'm concerned about inboard clearance for a 60's series tire. If they do rub on the springs, is there some kind of spacer I could use to move the wheel out a little? If so, where do I get/make them? Is this advisable? I really what to go with the Rallyes. I kind of like in keeping with the sleeper vibe.