If you find yourself planting your foot and experiencing a combination of bog and crazy pinging at wide open throttle with a Quadrajet, pop the hood, remove the air cleaner and make sure that when you push the secondary air door down with your finger that - not only do the doors go down, but the secondary rod hanger goes up. However more importantly, make sure that BOTH secondary metering rods are attached to the hanger, not just one of them...

I spent about 3 days tuning the carb, hunting vacuum leaks etc

to fix this issue, take a pair of pliers (fish the rod out first obviously) and without changing the geometry of the hanging length, bend the tang at the top of the rod to increase the severity of the upwards inflection to keep them attached to the hanger better.

Stupid problem to have i know, however the more people ive told about this, the more have experienced it at one time or another.

 

Happened again, the next and more permanent fix (hopefully) was to mix up a tiny bit of Knead-it, which looks like blu-tac and is a solid epoxy into a ball - not entirely sure what the equivalent in america would be (jb weld?) and apply it to the inside of the hanger so that the rod ends cannot slip through the holes in the hanger.

lets see how that goes.