Dr. Diff 10 x 2 1/2 inch or 11 x 2 1/2 rear drum brake Assy

65Vart said
Running discs up front

I assumed that. There are different diameter discs.

If running big front brakes 11" cordoba size use 11"rear. If using the smaller single piston floating caliper 73+ a body disc brakes use the 10.5