What are y'all using?

I used C body axles that were shortened by Moser. They called me when received and asked specifically what brakes I was going to use.

I used B body brakes 10' x 2-1/2". I sourced the backing plates from a swap meet for $10/pr. I already had a very nice pair of drums and had them turned. Found the Raybestos shoes at another swap meet and sourced the hardware and wheel cylinders from Rockauto. IIRC, the F-body cars, 73 and newer A-bods and M-body cars also used 10" x 2-1/2" drums in the rear but the E-brake attachment hole may be different in the backing plates. Whatever you use, the offset built into the backing plates must match the drums and shoes.

In my opinion, 11" drums on the rear of an A-body are overkill unless you are driving up and down Mt. Washington or Pikes Peak every day. Those drums are EXTREMELY heavy and will be slower than 10" drums because of the mass that must be accelerated. How many panic stops do you do consecutively anyway?

Using shortened C-body axles and those brakes increased my rear track exactly 3/8" per side. With the front 73-76 discs I look at it as having Road Runner-sized brakes on my 68.