Edelbrock 750 cfm stumble problem

Does any one have a mild 440 with an Edelbrock 750 carb? There is a stumble on take off but once you get past the first 1/4" of peddle you have to hold on. i have jetted it and changed the metering rods and the springs. any suggestions other than throwing this one away and putting a double pumper on it? Funds are low and the Edelbrock is brand new.
Author: 2002ram440