That’s a loooong post. I think I said before you NEED power valves on the primary side. And IIRC you said the carb builder said to not use them. Either way, they need to be in there and set the opening at 2 numbers lower than cruise RPM.
The second thing I notice is it looks like all 5 emulsion holes are open. There is no way that will work properly. You need 3 MAX and they need to be in the .024 range if you are going to use 3 emulsion.
Why are the carbs 3 circuit? With all the emulsion (and even when/if you correct that) you don’t need 3 circuits. Unless you have HUGE carbs on a small engine or you are using an oxygenated fuel or you are using E85 or methanol.
You didn’t mention idle feed restriction sizing. Are the IFR’s at the bottom of the metering block or at the top? They should be in the lower position. What size are the idle air bleeds? All those things matter. Or Power Valve Channel restriction sizing.
What size is the Main Air Bleed?
I could be wrong but those carbs need some work. You need to pin all those holes and write them down and post them here so we can see exactly what the tune up is.
This is where “Holleyitis” comes from. That thing should drive like a dream but it won’t with no power valves, emulsion that causes “slugging” which you are seeing in your wildly fluctuating A/F readings and that idiotic 3rd circuit.
Of course, these are just my opinions so take them for what you paid for them.
What a freaking shame.
EDIT: I just read your post again. If the 3rd circuit air bleed is blanked (no hole) then you do NOT have a 3rd circuit and that’s a damned good thing.
All the rest of my post is accurate. I’m just glad you don’t have a 3 circuit carb. That makes this way easier and cheaper to unscrew.
EDIT II: I just went back through this thread a few pages and saw pictures of these carbs. I forgot they have down leg boosters. I even mentioned that annular boosters are probably a better choice.
That said, you have what you have and you’ll probably need a SKOSH more emulsion with down leg booster than you would with annular boosters but certainly not all 5 emulsion holes open.
Hopefully that’s my last edit…