Making good progress!

Is this with the BBD, or the Holley?

I do not remember if you put a different cam in it, but if my memory serves me you have above average cranking compression..

So it seems to me that your vacuum at idle should be in the range of 17-20... Not that there is a direct correlation with compression but I believe there is an indirect one.. namely low compression can create low vacuum with a big cam.. But you have some compression in the engine, so that seems like there would be a bit more vacuum at idle.

Others know a whole lot more than I do about an AFR gauge, but my guess would that leaning out the idle mixture may help vacuum, and the "coast" AFR..

Acceleration and cruise both look lean to me...

This is still the Holley 1945, and I do have higher compression. I'm actually preparing to swap in a Super Six with a Chinese replica BBD. For now, I know I could get more vacuum at idle by advancing the timing, but I've kept the timing retarded (that is, at the factory setting of 0 degrees) to reduce the ping I have under load. I'm hoping the Super Six will fix all that, but we'll see.

The chinese knock up car is half the way to the NOS carb around. I hope it works for you, good luck

In the meantime, now that you have the AFR meter, could it be a good idea just to try fatter main jets and take reading?. You might have reached a plateau were a bigger hole does not matter, but at least you can investigate how all numbers change (and having a Plan B from the chinese carb).

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/6 Dodge Charger 69
...there's nothing like using the "Search" link above to solve most of your problems...

This goes for 160$

https://www.ebay.com/itm/NOS-HOLLEY-CAR ... SwNlleFZwb

I know you changed compression, and it is a Holley, but at least is an NOS part in good condition (hopefully, and even though is a 1945)

Also this one, but it says is for a 170. Not sure if there were differences on geometry, or just the jets.

https://www.ebay.com/itm/Mopar-NOS-1968 ... Sw5cNYPwUa

I give you these links in case the previous ones are already sold.

_________________
/6 Dodge Charger 69
...there's nothing like using the "Search" link above to solve most of your problems...

So I finally got around to removing my Dart's original kickdown linkage including that bracket with the D cutout that attaches to the transmission. Turns out the D is at an angle, same as the one I got off the 1979 Lebaron. As far as I can tell the parts are interchangeable.