Most likely the problem is not the carb if you had issues with two rebuilt units.
I had issues with my '83
H/O when I bought it, it ran rough, wouldn't idle and would die at random not to mention it would diesel upon shutoff.
I replaced the EGR and solenoid and it fixed the stalling issue some but not completely.
Then I noticed the factory block off plate was missing from the Air Bleed Valve and some idiot decided to "turn some screws" instead of fixing the problem with the EGR first which is a major no no with factory CCC Q-jets.
Turned out the Air Bleed Valve wasn't adjusted correctly, all I did was adjust it back to factory and all my problems went away, it was crazy the significance of this adjustment played in a number of issues.
It runs perfect now.
EGR can be a major factor, especially the solenoid.
Don't forget about the MAP sensor as well and don't use any aftermarket O2 sensors, they are junk.
Find an AC Delco one.
Always address the typical tune-up ware related parts first before turning screws on a carb or thinking the carb is the issue.