Here is my problem. I have a 33 Plymouth Coupe. I’m changing the motor to a 318 with a 904 trans. I am stuck on the rear-end swap. I would like to change it to a chry. rear end. The one that came out of the car is 51″ flange to flange. How do I figure the width of the new rear end so the new Cragar 15″ mag wheels will center under the fender and not rub on the wheel well or frame? I don’t want to cut or change the fenders or body.