Ok I have been having troubles with the Q-jet for like forever. Well tonight I did nothing more than adjust the choke setting because it's not hooked up to the pipe that goes to the intake as the Edelbrock 7111 doen't have it. Then I took the car for a run without the aircleaner on it. While I stil have a stumble when I floor it the engine will pick up and open the secondaries. With the aircleaner on it simply lays down and falls on it's face. So can it be the aircleaners fault, either by design, filter restriction, for interference from the base(of which it's had 2 different ones)?

 

Funny you should mention this as I just switched the edelbrock carb off of my 330 for a q-jet yesterday for lack of any real performance gain....bolted on the q-jet, (took it off my 350 from my cutlass) and instant power gain! I knew the motor had more in it! Set the screws with a vac gauge to where I had the most vac, adjusted manually the choke, and no more stumble like I had before with the edelbrck! Continually test drove, made adjustments, test drove again....everything great....then I put the aircleaner on...........WHAT THE HECK! Took it off, ran good again! Put it back on, no good! As I was loosening the wing nut, you could hear the idle change! Seems like the aftermarket aircleaner was barely touching the choke flap rod and restricting it....so I just didn't over tighten it and it seems better...running a K & N filter, so I don't believe it's for lack of air! Although, the secondaries do work on vac on a q-jet( at least on this one)...I'm getting ready to drive the car 7 hours to the Nats today...hope I make it!!!! I'm bringing the edelbrock carb just in case!!!! If I make it, maybe I can sell the edelrock to someone there!!!!

 

I have aftermarket open dropped base air cleaners on both my 66's and they can interfere with the air valve vacuum restricting thing on the passenger side of the qjet. I'm referring to the vacuum held rod which holds the air valve closed in high vaccum situations like idle and part throttle cruise.

Basically the lip which creates space between the air cleaner and top of the carb is a bit too short so the dropped base restricts the air valve opening or closing.

Adding a couple of additional gaskets solved this for me --- maybe 3 in total

Of course if you're using a factory base this problem shouldn't exist, unless you've added a different year qjet carb, holley, or AFB.

Hope that helps