Choke thermostat /RAGE

I was leaning a bit more towards the intake gasket leaking (or maybe a small piece of it got blown out from a previous backfire)....or...if you have power brakes, maybe the power booster is sucking air. Having that many carbs on and still somewhat the same problem, sort of eliminates the carb, almost. I don't think fuel delivery should even be considered; if the fuel pump can deliver enough volume to get you up to speed, it's not the culprit. This sounds like a off-idle lean stumble, but as Bill said, bypass that ballast resistor and check that out. 6v sounds very low to me.....I thought it should be over 9 volts on the "+" side of the coil.