The cam is missing from your carb. It raises the secondary metering rods out of their seats. The secondaries on all Q-jets are vacuum operated. If the secondaries open and the metering rods don't raise, the engine will bog.
There are a number of cams available and different size metering rods as well. The Q-jet is actually very tunable if you know how to do it, and in many applications will greatly outperform the average aftermarket carb. This includes the Edelbrocks and many Holleys, but the good info is not readily available.
I know a couple of guys who are wizards with these. I ain't too bad myself, but I fall back to them when I have problems. For a stock or mild street car I do okay. For a street driven car, there isn't a better carburetor out there!!
If you want, I'll put you in contact with my favorite Q-jet guy. He's in Nashville and is a well known drag racer.
