need help with 8 3/4 drum breaks

First off is it the original rear in the car...if it is it will be small bolt pattern and prob 10" drums...they stopped 8 3/4 in a bodys in 72.If its large bolt pattern..5 on 4.5 it is not factory to the car..could be B,E body.You need to find out if it is 10 or 11" brakes and get the correct parts.Measure across the drum opening and measure the width of the contact area for the shoes...they made alot of different size drums..9",10",11"