Pull the vacuum advance off and check total mechanical advance. I think around 36 degrees total (without vacuum) should be close.
The problem sounds like is may be in the fuel system/carb tuning. If you have too adjust the idle screws out more than about 2-turns, and increasing the accelerator pump nozzles/shot dosen't help, then you may have to drill the metering plate to open up the idle restrictions, and maybe the power valve restrictions too. If you don't want to drill the plate, you can get one of the billit plates with the screw-in restrictions.
This assumes there is no problem with the fuel pump/lines, and only the carb needs adjustment.