Stop in for a cup of coffee

LOL. View attachment 1715879495

When below 14"Hg it effects the flows through circuit restrictions, so I use that as a reference point.
However when around 11-13" Hg isn't that bad for a hot rod.

Anyway, the spec from QF is helpful. One restriction we would really like to know in this situation is the Idle Feed (IFR).
Three things control the amount of fuel being moved toward the intake when the throttles are in idle position (and off-idle)
1. Idle feed restriction
2. Idle Air bleed
3. Transfer slot above and below the throttle.
If an engine is stock or close to it, I consider 15hg pretty crappy. It should be more like 18-21. Course I say that with a slant 6 that idles at 6hg. LOL