I have 4 options:

If your car is a dart sport you can use a b-body rear end no problems.

If not find a 8 1/4 big bolt pattern and build a rear end.

If the car is a regular dart use a b-body and buy the offset rims.

Save money and do it the right way.

All will work some easier than others.

56 Plaza 63 D100 step side 67 Coronet, 68 Roadrunner, 69 Super Bees, 69 Coronet 500 convertible, 70 Roadrunner Post, 79 D150 360, and a severe case of Mopar a,d,d