I am having a huge problem. My car has been for what ever reason quite reluctant to run properly. I have a 250 I bought an Offenhauser intake for,and put a Quadrajet carburetor on top of it.
and It starts stays running for a few seconds and If I don't feather the gas on and off it stalls out. After a while of doing this It just barely manages to run. To me I thought 'vacuum leak' I can not find the problem. The nature of the Q-jet keeps the large secondaries from opening. Is it possible that even the small primaries are to big? Is it possible that I need a spacer plate? I am pretty lost on what to do. I adjusted air fuel,idle. I sprayed carb cleaner around the intake and carb as it was running and no effect. To top it off after it warms up enough to stay running I throw it in gear and it dies. I brought up the idle and then it slammed into gear even though I only brought it up about 200 rpms. What are my options? What tests can I do to determine the problem. I really need a more experienced mechanics help.

Do you have another carb you could try to possibly eliminate the Q-jet as the problem.

Forgive me if this sounds silly,,
That sounds exactly like it's running out of gas. (Badly plugged fuel filter?) Those carbs have the little filter just inside of the inlet don't they?
If I didn't "know" that particular carb,, it would be my prime suspect.
Maybe you have a buddy with a known/functioning 4v of any kind that would let you borrow for a test.

Adjust your idle where you like it with the tranny in Park. Hook up your timing light and see where the initial timing is at. Put it in gear and see if the initial timing changes. If it changes disconnect the vacuum advance and check the timing again. Let me know what you find.

Ron

I will try each of these tomorrow- I will feel really stupid if it's the fuel filter, I did replace it but thinking about it it is a likely culprit. The car has been sitting a while and was relitively low on gas until a few days ago. I think I just switch to an inline fuel filter I like seeing my fuel-help diagnosis,maybe.

couple ?'s,, I'm running this carb on this manifold,, how did you adapt,, the offy is set up squarebore, if you removed the plate and fabbed up a spread to square flange carb adapter,, some q-jets don't like to run with a floating middle,, meaning one giant hole for the gasket,, you can buy a thin spreadbore plate to solve this, it may help feed correct vacuum to the passages that need it,, I also had an issue w/ a q-jet that came rebuilt and somehow a 301 pontiac base came on it,,"turbo application", the carb never ran right, there is a vacuum passage removed that attaches to the primary rod passages, there is a stagigic hole that can be drilled to make it a standard base,,,if the vacuum doesnt get there it runs way lean and screws up the primary circuit,,,, weird carbs to get used to working with,,,q-jet rebuilding by Cliff Ruggles is a 'bible',, if ur gonna get into these carbs,, to see if the primaries are funtioning there is aliitle plug that is removed top center of the carb, if I remember right they pop up under throttle if they always stay down they are messed up,, if you have an 'apt' q-jet these are adjustable and sometimes get stuck,,,

Well I test the advance it works fine,I put a new inline fuel filter on. I had this car running with an edelbrock carb. But It does not work in my application. As I have a throttle rod and the edelbrock mounts differently.

For the Edelbrock, use a bellcrank setup to actuate the linkage.

Well after a few months trying to figure out the problem I asked my cousin if I could borrow a q-jet he had around I put it on adjusted it a bit an problem gone. I suppose I will have a few complaints for the guy who rebuild my carb.