Jim:Years ago I raced my 230 horse '56 Bird in NHRA stock. Some things I tried that did not work. Putting a screw in the secondary throttle slots to make them mechanical instead of vacuum. Larger or smaller jets. Substituting non-dual carbs for the dual ones to try to get more airflow with the less restrictive boost venturi. Boring the secondary throttle bores oversize (not legal, but at least I didn't bore the original '56 dual carbs). Playing with power valve springs. In a nutshell, I found that the factory setup was the best I could do. Mine was a '56 setup, which was an over the counter racing kit, so may have been optimized by the factory or a Holman-Moody type shop. I did convert to a fully mechanical distributor. I found that 6 psi fuel pressure was adequate and did not cause flooding.
I remembered an article in Y Block Magazine about dual carb tuning, so I looked it up, Issue 72, article by Dan Del Duca, '57 E Bird and a pickup with 2-4s. He said he opened the manifold under the carbs to make open plenums, which he thought would reduce low rpm torque, but it seems better. Undocumented opinion. His carb tuning amounted togetting them rebuilt and recalibrated by his "carb guy". No information about him or his modifications other than enlarge some fuel passages because they were so long.