truck stalling, possibly carb issue?

[slam59]

This is the second time my wifes 77 c20 has done this. Has a 454 motor in it. While taking off from a start and accelerating it stumbles and as i press down on gas it goes nowhere just coast a bit. Then I would pump gas slightly and then it finally would accelerate. It almost would feel like I was out of gas or not getting gas into carb. Well after that a few days later I gave it a much needed tune up. New ac delco plugs with some good msd wires timing was set and even sea foamed it for the first time and man oh man that sea foam really made a difference in acceleration and a good smooth idle. Kid you not this truck has NEVER ran so good ever. Also put a new fuel pump and fuel filter. That was 2 weeks ago. Well just this morning went to take stuff to the dump and upon leaving as i drove out the gate on flat land it did it again. as i was slowly pulling out as i accelerated it would not respond. It just coasted so I pumped the gas and it did not help. so i stopped put it in park, revved up the motor off and on for about 30 seconds and it seemed to respond normaly upon pushing down on the gas pedal so then i put it in gear and drove off. I had about a 4-5 mile drive home and it drove like a champ the way home. Since i am getting plenty of fuel to carb with new pump and filter, and such a good tune up done, can it be the floats in the carb getting stuck and or needing adjustment? It is an Edelbrock carb. Just saw a show where it happened to these guys and they opened the carb and moved the floats and linkage around and it drove after that. What you guys think?