You need wheels with a larger backspace. They sell 15x7’s in the wrong backspace too, so just going to 15x7’s may not fix your issue.
Other than having a ‘72 Dart, how is it set up? What rear axle is in there? Is it the small 5x4” bolt pattern or has it been upgraded to 5x4.5”? That will make a difference with what you need for wheel backspace. You can run 15x7’s or even 15x8’s and re-use your current tires, but the backspace will have to be right either way.
