1972 swinger tire sizes, ansen sprints

You'll need the 15x7's up front, and really you'd be better off with 4.25" of backspace like the OE mopar 15x7's had. With a 15x7 and 4" of backspace you'll probably only get a 215/60/15 in there. 225/60/15's on those rims would be closer to the fender than my 275/35/18's up front, so 225's are out unless you want to modify the fenders a bunch. And 215/60/15's aren't recommended for a 15x8, so, go with 15x7's.

In the back the 15x8's with 4.5" of backspace should be ok, but with the springs in the stock locations you won't get 275/60/15's in there. About the widest you can go on a Dart with the stock spring locations is a 255/60/15, and that doesn't even fit on every car. Most need to trim the quarter lips to keep 255's from rubbing. 245/60/15's are probably the widest you want to go unless you're willing to cut/roll the quarter lips. And the backspace will depend on what how wide that 8.8 is, I know you say "stock width" but stock A-body 8 3/4's with SBP are about 11/16" narrower than when they're fitted with BBP axles, and 7.25/8.25 A-body rear axles are over an inch narrower than the SBP 8 3/4. So, how well that 4.5" backspace will center things really depends on exactly how wide that 8.8 is.