Non self adjusting rear drum brakes on a Dart?

Cobra-sma/Braseixos is a company that makes auto/truck axles today. So what you have there isn't Mopar, or Dana. It's a Braseixos! Maybe a carbon-copy of a GM 10-bolt, or simply made for GM (and Chrysler?). Very unusual.
Yes, we are back to 1970's, Braseixos was manufacturing that same axle for gm light trucks as well. Easier for Chrysler to use them than importing parts and pay taxes or make Braseixos manufacture the US versions, once they never manufactured a substantial amount of Darts in Brazil. I think the whole 12 year production since 69 till 81 never added up to 100k units and after 76 not even 20k were made. Gas became really expensive...