Hopefully some other peeps with more experience will chime in.
If you run your engine size, planned RPM's, and volumetric efficiency through a CFM calculator it shows your engine needing a smaller carb, but that may not be the problem.
I read an article in HotRod mag. or MoparMuscle mag. w/e and they had a similar problem. They had taken out the (2) metal filters on their Holley DP where the fuel lines mate to the carb. Problem went away when they put both filters back in. I think that would mean that the fuel bowls were filling up too much when they lifted off the throttle. May be a float adjustment thats in line? Just an idea.
Either way, I would make one change at a time and then go test drive your vehicle.
Bad Shrimp