I'll start with the usual WOW - Best $300 dollars spent! I wish I would have purchased a weber for my first 2.6 13 years ago. Some great write ups on here which helped along the way. Weber with upgraded exhaust makes a world of difference (2.25" piping with high flow cat and FM series 40)

I went with the Holley 1-4psi regulator which I have dialed in nicely right around 2.5psi.

Situation - I wanted to dial this in to the best of my abilities. Knowing one of the most common tools for monitoring carburetor adjustment is a vacuum gauge. When I connected the gauge I was seeing right around 18in-hg of vacuum, and the motor ran well; After spending some time tuning, I was able to get almost 22in-hg - very surprised to be honest, and actually made a noticeable improvement in drivability.

Question - I know the procedure for adjusting via vacuum gauge, but I really want to know how the higher vacuum reading cross talks to A/F ratio. Will the motor idle best at stoichiometric? I guess I really want to know why using the vacuum gauge is such a trusted tool for dialing in your A/F...

I hope that reads pretty clear.