Narrowing rear diff.

I had a C-body housing narrowed to 46 5/8 (A-body housing is 52 5/8,minus brakes)so basically 3 inches either side of A-body length.I fit 15x10,s and 15x12 under my 66 Dart with a minitub and 3 inch spring relocation.Rims are 4.5 b.space