GlennLever and the boys,
I have been reading these posts from some very knowledgeable Weber tuners. I am a little surprised we haven't started from the beginning sota speak.
It is absolutely mandatory that the idle speed screw be at or slightly less than 1 1/2 turns in from the "COMPLETE" closed position.
You would read ZERO vacuum at the "S" ported vacuum source to the right of the choke and down on the mounting base of the carb.
I am quite sure you are not there "yet".
Slow the engine down as slow as you can with the Idle speed screw on the carburetor.
Then, readjust the ignition timing. Typically we are taking the distributer out of it's centrifugal advance. (aprox 8-10 btdc)
With a .75mm primary idle jet you should find the "lean best idle" somewhere between 1 7/8 turns to 2 1/4 turns out.
Where are your settings, do you know what jetting you have?
Shaun makes a great point about the F7 emulsion tubes in the secondary barrel, that would be after we get this to smoothly accelerate through the RPM range.
The 32/36 DGEV is and has always been an economy alternative carburetor. The 32mm primary barrel will work on a stock 4.2/258 engine, then at 1/2 throttle start to open the secondary barrel.
The 38 DGES is virtually the same size as the OE carb BBD, and is not considered "over carbureted", as it is the same size as what was originally designed for the engine. (Same as the MC2100 & MC2150.)
REDLINE claims it is the "mandatory" choice if you have upgraded your engines performance.
REDLINE did these conversions for the 258 Jeep many many years ago using the 38 DGES, as it was the same size as the BBD, (makes sense). The industry clamored, begged and negotiated for a better prices.
At a certain point the only way to make it cost less was to use the 32/36DGEV which at that time 25 years or so ago was $50.00 less than the 38DGES, that is a big deal when it comes to the reselling price.
Let us know where your settings are, or try to get your setting at the bottom line base line settings and we can see where this takes us.