Too much cam?

Sounds to me like carb opening too soon and/or not enough pump shot. I know you said you messed with it but did you try the heaviest black spring on it? I have had to run the heavy black spring on both my last combination's cause they have so much vacuum it sucks the vacuum secondaries open almost immediately causing a bog. Also had to go with a bigger pump shooter than the stock size. Changing position of the pump cam doesn't do squat for the ammount of pump shot you get initially. Just increases duration.

If it is truly a dead/flat spot on initial acceleration it's not that the cams too big. It's going lean.