I HAD THE SAME PROBLEM on my mild 440
after chasing it for 1 year and trying 3 diffrent carbs including demon and holley and edelbrock which did the best i found it to be a intake manfold problem. i had oringaly blocked the heat crossovers on my ch4b and it caused the fuel to not atomise. i took the crossover block out and havent had ANY problems sense. so if its blocked fix it. old man mopar wouldn't have a heat crossover if he dident need it.

is the problem worse with a cold engine if so it means it gets better with heat. so heat the intake!!!!!