Big bolt pattern axles drum brake

ok normally people just change out everything. While this puts lower cost parts with better availability on the A body it adds rear brake to a car with too much rear brake already.
The Mopar B body six and 273 cars came with a 10x1 3/4 drum. That drum is hard to come by but that is one way to retain the A body brake.
The other option is to use an AMC drum. Yes they work. Yes the register is the same size. Yes the offset is correct.
I’ve done it. You retain the A body backing plate and brakes. I found a pair of original AMC drums that look like the 70 up “darth vader” drum.