quadrajet
The air valve shaft has a screw on the passenger side. Hold it with a small screwdriver and loosen the vertical allen set screw under it. Like said, only tighten spring 1/16 of a turn at a time. Not more than 1 1/2 turns total tension or the spring will stretch. You might want to mark its original position in case it slips. With the car running at idle, if you open throttle quickly, momentarily, the air valve should just barely tip in.
Also the choke pull off diaphram has an orifice in the end that attaches to the vac hose. There were several different size orifices originally. Or you can measure the hole with a number drill bit, epoxy it shut and then redrill it a smaller size. The smaller the hole, the longer delay till opening. .026" was a commom orifice size.