Selecting power valve method Holley 4160
If the hesitation occurs as you are mashing the gas from idle, then, before you do anything, increase the rpm by 100, retime the accelerator pump as may be necessary, then see what happens.
If this improves the situation, but the idle-rpm seems excessive, retard the idle timing, which is the only way to reduce the idle-rpm, once the Transfers are set..... unless you can figure out how to increase the Transfer slot fuel delivery, at a smaller throttle-opening.
IMO, tuning with a vacuum gauge is a waste of time.
Does this mean I need my secondaries to come in a little quicker?
no. it means the vacuum changed, is all.
Engines do not suck air in.
Air always moves from a high pressure area to a lower pressure area.
When you open the throttle valves, atmospheric pressure being greater than the pressure in the intake, forces air into the intake. An automotive vacuum gauge is not a vacuum gauge at all, rather, it is a pressure gauge. It measures pressure. When it is disconnected from the engine, it measures atmospheric pressure, and the guy who invented that gauge, simply calibrated that normal resting place with a big fat zero on it, but really, it is measuring about 14.7psi.
The closer to zero(14.7psi), that your gauge reads at WOT, the closer the intake is to normal atmospheric pressure.
This has zero to do with the timing of the secondaries. The dreaded bog, has everything to do with the timing of the secondaries. For a low 60foot ET, the bog has to be avoided at all costs.