Well no it's not, that's my point. The analogy would hold if your toilet was instantly ready for another flush in a thousandth of a second. While the design is sort of similar the carb fuel bowl doesn't ever drain all the way down it tries to stay at a constant or minimum level at all times under all conditions. When they spec the fuel height level in the bowl at +/- a 32nd of an inch, that's the "tell" that it's kind of a precision tolerance. The float is under constant upward pressure on the high side, remember even the lowliest mechanical fuel pump can flow at least 15 gallons an hour at idle, way more than those engines could ever use. In operation the carb float doesn't even visibly drop, near as I can tell.
I can tell you for a fact, the floats drop in Q-jets. When the system can't supply the need fuel, the power drops dramatically in the top of first or second gear when the demand is the highest. Been there done that more then enough times to know whats going on!
I'd like to see some transparent Holley float bowls. Just to see what the heck goes on inside their at idle, wide open throttle.............be interesting.
I don't know much about Q-jets, Holley needle and seats come in a bunch of diffrent sizes for more flow, from .097 to a stainless .150 that guessing is for running alcohol. Built a 1050 using the Q-F 1050 body and metering blocks for my drag car, started to tune with out the power valves "pluged the holes like always on the drag car ", had .130 needles and seats in the bowls. Seemed to hit a wall at #96 jets, was not at 12.5 on the A/F gauge yet and larger jets would not change the Mix, so called Quick Fuel and the tech was real short with me, Stated put the power valves back in with out an explaination why? Put them back in and jetted down for the diffrence they make and now had enough room to tune. My guess is that the channels in the metering blocks could only flow to #96 jet and the power valves by passed the channels to deliver enough fuel Barry Grant had a fuel delivery chart test showing how many seconds it should take to flow a gallon of fuel for 1/4 mile cars, I remember a 10 second car should flow a gallon in 23 seconds.
On the Qjet, years ago I installed a GM part number for a needle and seat set that had a larger opening than the factory one on my 350 SBC.
I bought this old Holley 1904 from a going-out-of-business junkyard seven years ago. It was on a '57 Ford, I believe...it just goes to show that Holley has tried it!
Right, well it kind of sounds like what you're describing a defect. In any case all of this has been engineered into the carburetor, it was calibrated from the factory to have a very specific fuel height level in the bowl at idle. They tell you to check this as part of a Tune-Up or replacement. They did this for a reason. Give the carburetor what it wants, and it will give you what you want. See where I'm goin' with that?
These carbs had a solenoid activated "enrichment valve" (or similar name) instead of a power valve, and an oxygen sensor. They were constructed to run lean as a default, the enrichment valve pulsating open and shut to provide extra fuel to provide a correct ratio for cruise, idle, acceleration etc. as directed by the engine control electronics. The dwell meter was used to check the percentage of the time the enrichment valve was being instructed to be on. I guess the inline six is more forgiving. My last car with a faulty accelerator pump system was very difficult to get moving from a start without stalling (auto transmission).
Tuning for 70s era federal Emissions is "interesting", because they pretty much had to cripple that era of motor to meet regulations. Turns out the optimum tune for any engine of best mileage, best performance, is also the peak of NOX output relative to HC and CO. So they traded one kind of pollution for another, and killed any semblence of power, performance and economy.
NOx is formed at high temperatures, so it's rather logical that we get the highest amount when the engine is running "best" - the best, most efficient combustion will also be the hottest. Reducing the compression ratio is one way to reduce the temperatures, unfortunately it also reduces fuel economy and power.
The Jalopy Journal
