69 Dart Custom tire issue

You can also have your rear axles re bolt patterned to the 4 1/2" . Any machine shop can do it. Thats what my car has.
15x8 wheel, 4 1/2" backspace , 255x60x15 rear tires. '69 Dart. I had the large 4 1/2 pattern on the fronts, newer DART, '73?
You have choices.