75 Dart Sport Tire fittment

You have your backspacing "backwards", I think.
The more backspace a wheels has, the less "dished out" the wheel is.
Therefore a 15 x 7" wheel with 3.0" of backspace will stick out further then a 15 x 7" wheel with 4" of backspace.

Check out this site for the best quick reference wheel info I've ever seen and learn how to find the backspace and such.

https://www.rsracing.com/tech-wheel.html



If you are are going to buy a 15 x 8" rear wheel I'd recommend getting a wheel 4.5-inch backspace over a 4" backspace wheel. Wrapped in a 255/60R-15 will fit the car great!

As for the fronts... I have three sets of aftermarket wheels on A-bodies right now, all of which are skinnies. They are:
A pair of 15 x 4.5" slotted mags with 2-inches of backspace
A pair of Centerline Auto Drag 15 x 3.5" wheels with 1.65-inches of backspace
A pair of 15 x 5" Weld Pro-Stars with 3.5-inches of backspace

I'd like to find a nice set of 15 x 6.5" wheels with a 4.5-inch backspace for the front, but I haven't seen any off the shelf wheels like that.

I would recommend a 15 x 6 with a 4" backspace for the front. Though I do not know if you could find any of those.