14x7 Magnum 500's on a 68 Dart

Just wondering if anyone has had any problems fitting a 14x7 Magnum 500 on the rear of a 68 Dart. They are from Specialty Wheel and I think they have a 4 1/8" backspace. I haven't put my 8 3/4 in the car yet so I don't have any measurements yet.Thanks