Cruise Seems Lean

71GSSDemon said

I do failure analysis on engines (new, modern fuel injected overhead cam, etc) for a living, so I am comfortable with most tests, I am learning more on the testing/tuning, etc on our carb engines.

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Awsome. A long time ago I was involved with design validation testing for airbags. My coworker mentioned above was a mechanical tech there, and I paid the machine shop to turn the air bleed restrictions which eventually went into that 3310 pictured above.

A few rules of thumb.
The "idle" circuit can be extended into higher throttle opening without changing the mixture by changing the IFR and the IAB proportionally. In other words a larger or smaller pair will get the same ratio but choke off flow later or ealier.

The main airbleeds in combination with the "emulsion holes" can effect the initiations of the main circuit. Increasing or decreasing the main airbleeds does not always do what you expect in this regard. Big changes the main jets may require a matching adjustment in MAB.
Can read the info in this post and the second post for more about these relationships.