I have tried 8-12 degrees initial BTDC, no change.   I had the vacuum advance can rebuilt recently and it is working.   I have a few questions I will ask on the other thread

You might try an additional 4° of initial ignition timing.  Also check that the vacuum advance is indeed working.  You can do that with a timing light and lightly speeding up the engine while watching the movement of the timing mark on the damper.

See if this link to a recent thread helps in regard to checking out the economizer circuit.
Holley 4000 teapot carb (y-blocksforever.com)

Lorena, Texas (South of Waco)

Is there a way to test the power valve and economizer?   My 55 Thunderbird 292 automatic has a slight hesitation when flooring it at a dead stop.
The accelerator pump looks to be squirting from both sides OK.   I tried the two adjustments on the accelerator pump, there was no difference