New wheels

As stated above (and based on all of the research I did) you won't need spacers for the rear. The B-body rear ends are ~1.5" wider (per side) than the A-body rear ends. Stock backspacing on a lot of 7" wide Mopar wheels is 4"-4.25". Adding the 1.5" width of the rear equates to about 5.75" of backspacing, and these wheels have 5.72" of backspacing.

You should be set out back.

You may need a 1/4"-1/2" spacer in the front to clear the tie-rod ends and to reduce interference when turning the wheels. May not be needed with disk brakes (wider track width than drum brakes) but I am not 100% sure on this.

-Mike