Cliff's Quadrajet Parts and Rebuild Kits

  Still curious about how the size of the main nozzle air bleeds affect the AFR, and the relationship between these and the main jet size.
 Cliff?

Sorry.  New to the quadrajet terminology.  From reading about a plugged secondary air bleed tube it said this condition would result in rich idle conditions.  This can't be true since my carb runs extremely lean.

I have found that the idle/low speed mixture is predetermined by the idle tubes/jets and the upper and lower air bleeds and any idle bypass air.
The amount of mixture, on the other hand, is determined by the channel restrictions and the mixture screws.
The off-idle slots acts like additional air bleeds above throttle blades and changes to idle mixture discharge nozzles when thottle blades passes the slots at greater throttle blades openings.

So you cannot get a leaner or richer mixture from the mixture screws at idle, only more or less volume of the mixture.

Plugged POE

 That carb does not have the POE, (pull over enrichment), what you have circled in your picture is the secondary air bleed tube.
 If it had the POE system, there would be a 3rd set of tubes located in the slightly larger holes just ahead of the air bleed tubes, and these would be longer and thicker. In addition, the discharge holes for the POE are located just above or below the choke blade when it's closed.
 If those are not there, the carb never had a POE system. If there are discharge ports, then it's possible that someone pulled the tubes at some point and didn't replace them.

That's what I do, & if you drop it carb has to come off.

 I'll probably pull the carb off to swap any of these just to be safe. I've got the process down to a couple of minutes and two tools.