Yes Tim you are hard headed , it's that 1411 carb , it's a PIECE OF CRAP , PERIOD , end of story. Look for the carb test fast68plymouth did some years ago and he specifically had horrible results with an ebrock preformer 750.

The heat riser is making the problem 2 fold, you have the heat passage open under the intake ... i assume ... and the new fuel formulation getting boiled out of the carb. insulating the crab from the intake don't matter , heat RISES , the heat from the open passage is rising up thru the carb and it's evaporating the fuel.