A little more oomph

jrc,
Some other tidbits about carbs, Carter 4 bbl in particular.
Carter had a vac sec model AFB in 1957, the first year of the AFB. I have one, pretty rare. It was quickly consigned to the dustbin of history....
Presumably because it didn't work as well as expected.
Try & borrow an AFB so that you can strip it down. Unlike a Holley [ or clones ] you will not need a pile of gaskets if you are careful. You will be amazed at the clever construction, the sophisticated yet compact boosters, how close the primary jets are to the venturiis for quick fuel delivery/throttle response. How it is impossible to mix up the booster bodies.
The AFB has an ingenious 'starter cct' in the secondaries to help reduce bogging; the Holley does NOT.