In the intake side pic you can see #1 carb slide is way high compared to #2.
You did re-set them to same height?
High vacuum is caused by slide completely bottomed out compared to the other slides, you did try turning the adjuster the opposite direction to see what happens?
You could also have something assembled wrong?
If you ghave some od pilot jets, push them into vacuum lines, it will slow air movement, particularly if 'idle' speed is too high