had a 600 eddy on a 318 that I couldn't get the bog out either, with stock converter and 2.76's. But I finally got the bog out with one word..... "Holley" :D
I bet the Holley is a vacuum secondary. See, that's the difference. The Edelbrock AFB carburetors are mechanical secondary carburetors. Although they do have the air door to regulate air flow, they are 100% mechanical in nature. That's why they need some RPM to make the transition smooth.