'73-'76 A body upper control arm, doesn't have to be disc, drum is the same '66-'70 B body spindle with 10" brakes (11" will work also) both are common parts and should be easy to source
Lots of advantages -5x4.5" vs 5x4" pattern -10"x2.5" vs 9x2" / 10x1.75" -less $$$ than aftermarket discs -repair parts from the local parts store
ditch the adjusters so you can adjust the brakes for zero drag the big '66-'69 11x3" brakes didn't have them to start with
