A reverse wheel has positive offset, and a lot of it. Meaning, a very small backspace. If you want to run the widest tire possible, AND fit the wheel into the stock wheel tub you need a negative offset, not a positive one.
You can run a 15x8 with about 4.5” of backspace (depending on which rear axle and brakes you have) and a 275/60/15 on a ‘73 Dart Sport with the stock spring locations and fit it into the tub.
But that’s not anything you’d call a reverse wheel. You can run chrome reverses, but you’ll have to hang the wheels out past the quarter panels and raise the ride height substantially so nothing rubs with suspension travel. Or run wheels with the right backspace to fit in the tubs, but those won’t be reverses.
