Spring re-location?

Hey Bobby, the 73 darts have a longer wheel base i think, maybe theres more room in the stock wheel well too vs. a 71, i had a 73 swinger, & i remember stuffing 255/60/15s under the stock well on 15x8 welds, if i can get 245 or 255/60/15 DRs under it with a rolled lip & moveing the springs in with the offset kit i think it'll hook, it shouldn't take much to get this SB to hook with a DR, i'll be clamping the springs, better shocks/snubber & currected pinion angle.

Does anybody know what offset rim i'll need if i get a 15x8" rim running stock axles?