Well, from your description, I don't think your "bog" is much related to these holes.
These holes create a problem at Gentle tip-in,when the carb goes from rich idle to slightly lean to probably normal.
From your description, your "bog" is more likely an accelerator-pump problem, possibly handicapped with a tight TC.Also, with the Tblades so far closed, sometimes the timing is in error to compensate, and sometimes the A-pump linkage does not activate the pump on que. Without the pumpshot being on time and strong, the engine "bogs" until the mains start flowing and the PV comes on line.
The recovery with the second pedal-stab says it all.That accomplishes two things; first is time, and second is more pump-shot.It takes time for you to back-off the pedal and restab it. During this time the engine is unloaded and makes a partial recovery. Then the fuel from the second stab gets there, and now the incoming air-charge has the velocity and the correct mixture to not bog, so away you go.BUT, if the secondaries try to open this early, and you have a tight factory stall TC, then all bets are off;the bog is almost insurmountable.To open the secondaries early,especially as the cam gets bigger, You need two or three things 1)a looser TC to let the engine "freewheel" a few to several hundred more rpm, to where the airspeed through the carb is sufficient. and 2) higher compression/low leakdown.In this case the compression is not actually the requirement. No,actually what is at work here, is the fact that the rings are higher up the cylinder wall,and when the piston starts going down.This, coupled with a very low leakdown, will encourage the atmosphere to begin ramming air down the carb a tiny bit earlier. Earlier. 3)From a standing start, gears won't help this at all. But from the moment the car starts moving, a performance gear-set will present a smaller load to the engine and it will rev up quicker. And that leads to the next thing; Gears do two things. 1) they help the car get off the line quicker, and 2) they help the engine put more average HP down per unit of time. And not much else, except if the correct set is chosen for your driving requirements, it can make your driving experience so much more pleasurable.For instance, For me, having the right gear available at 30/35mph is very important. I only have a 360,and it is saddled with 3650 pounds and manual trans, so it needs to be helped to get moving at all times; but even more so, when I want it to.But I also want to hit the hi-way,cuz I live 20 minutes from the nearest small town, and over an hour to our capital city of Winnipeg so hiway miles is always on my mind. Getting back to gearing at 30. My engine torque peaks well into late 3000/early 4000 rpm somewhere, which means it's a bit soggy off the line. I don't care about that. I care that at 30mph when the hammer drops,stuff has to happen. Also at that speed I want the car to be quiet, cuz I spend a lot of time at that speed.So, to that end, the car is geared to make that happen in second gear. Then when it's go-time, a quick downshift, and it's KABOOM!,we are moving!.
So, as much as I might want to fill those holes, I would fix the bog with the pumpshot and timing first. Perhaps the tip-in, with those monster holes, will then show up. And if not then you have saved yourself 2 hours of work. Of course me being me, I would still plug those holes, cuz no good thing can come of them,with a working PCV system.
And in case you haven't figured it out yet, the PCV system,to the engine, acts as a continuous automatically adjusting air-leak. At idle,this leak it is fixed by the manufactures designed in calibration bypass. As vacuum decreases, the little valve inside there is allowed to fall away from the fixed orifice, and the engine draws more and more air through the breather mixt with crankcase fumes. Eventually the vacuum starts to fall as the T-blades open further and further with gas-pedal increases.So now the valve hits it's maximum travel stop and air passing through it may be limited by the factory design. So now the crankcase fumes have to escape somewhere else or blow out a seal somewhere.Well the factory method is to reroute those fumes through the breather in reverse-flow and back into the filterhouse to be drawn into the engine through the carb,Voila.
The problems start when a big cam goes in. The reduced idle vacuum may allow the automatically adjusting PCV to open and this may disrupt the idle quality, as the PCV hunts around to find equilibrium. The usual fix is to get rid of it, and drill those pesky holes in the T-blades to compensate for the flow,lost through the PCV. If/when the cam gets still bigger, and the idle vacuum falls yet more, then those holes have to be increased ever larger.So it would seem that your carb has seen duty on a big cammed engine or at least a larger displacement engine, or the guy who drilled the holes was just on a different part of the learning curve,or he was limited by circumstance. In any case, the carb is restorable,so no worries.
But let me repeat these holes are not your "bog" problem; at least not the major part. Fix the pump-shot issue first. And if your combo is off,due to a mismatch of; carb-size,secondary-timing,cam,TC,compression,and/or gears,You may not be able to get completely rid of it.
