How would you check it? You have to put the screws it together and put the screws in and then you can't get between the actuator and the pump itself?

Maybe a stupid question but in my mind at least it doesn't seem clear to me.

If I remember ... The linkage on the side of the carb has a rod that goes towards a lever on the front. That lever pushes a button which presses the diaphragm that forms the accelerator pump. If the linkage has been 'adjusted', it could be too far into the stroke of the pump to squirt appropriately. The opposite would be true if there were clearance between the button and the lever.
I still believe that the VENTURI vacuum, which increases with full open throttle, is used to open the power valve. Manifold vacuum could be at zero, while venturi vacuum at its peak. That is why it sucks the gas out of those things hanging right above the throttle plate. If the float level is too high, you'll get crappy mileage as the vacuum can draw the fuel over the 'top' so to speak to readily. Too low, and you won't have enough fuel flow. IMO.
tom

Not venturi vaccum, manifold vacuum which is lower at WOT opens the power valve. Look here for how the power valve system works.

http://www.holley.com/data/TechServi...wer_valves.pdf

Here is where all your carb questions will be answered.

Holley Performance Products Technical Library