[geezer#99]

Quadrajet had an air door that had an adjustable spring on it. Guys would set the spring looser and the door would flop open and bog city.
Eddy carbs also have an air door. Only adjustable by adding or removing weight of the counterweights on the door.
Both quadrajet and eddy carbs also had a secondary lockout feature. Linkage that only worked when the choke was fully or partly on during motor warmup. Once warmed up the choke would be completely off, the linkage would drop out of the way and the secondaries would work.
Secondary lockout was needed to stop wide open throttle operation on a cold engine.