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

I would say,depends on wheel/tire size.
15" wheels under 10" width.
Tires less than 28" diameter 12" cross section.
10x2.5 should be fine for stopping.
A larger combination, you may need 11x2.5.