Carter Thermoquads ~ 'More General Information'

4bbl,
Couple of comments. The AFB, AVS & QJ also used two idle air bleeds, so not unique to the TQ.

You brought this up before about the air bleed function of the space around & above the m/rods/main jets. These are not ABs because ABs occur after the fuel has been metered; this is just atmospheric pressure acting on the head of fuel. No different to AP acting on the head of fuel of a Holley jet, except the H jet does not have a m/rod in it restricting flow. The fact that a brass bush was used to guide the m/rod on the CS; maybe be deleted on later models because it was found it was not needed.