Dual quads versus big hammer!!!...

Ok, I see what you are saying. I wish I had one here to look at.

Essentially, when discussing the metering rods/springs we are talking the power enrichment circuit, which is the same as the power valve circuit for a Holley. They function the same.

That's why I asked about cruise vacuum. You should be able to pull the main jets completely out and it shouldn't affect idle.

If you are using springs based on idle vacuum, a big portion of the lean spot you are seeing in transition my be from the metering rods coming out of the jet too late. Especially with a stick you see a bigger hole right there. You can cover it up with the pump shot, but that means you may be using more fuel earlier in the pump stroke than you need.

Obviously I don't think this has anything to do with the air valve doors opening or not opening. But I think I has something to do with the lean spot you are seeing when you mash on it a bit.
What do you think of this scenario? You have a 238-248 duration cam, 354 gears with 28 inch tall tires, and you're cruising at about 1800 RPMs and you just mash the gas out of nowhere?... Mind you this is a four-speed so it's not going to downshift into 2nd or into first and smack the RPMs up real quick... ?