stanman

I swapped the carb from a q-jet to a holley 390 for economics.
runs rough before being warmed up. slightly bogs and spudders.

I put the q-jet back on and its fine.
the q-jet has 4 vac lines and the 390 only has 2.

I adjusted the fuel/air. but still facing the same issue.


options: vacuum not set up correctly. Needs to be re-jetted.
or carb has an issue.

what do you suggest?

Camaro 69

Could be a choke adjustment issue, but a 390 cfm is a bit tiny for a 350.

eturner

i had a 400 sbc and i had an old worn out q jet on it, so i went to the pick n pull and grabed another one and when it was cold it ran real rough, but that was because i didnt hook the choke up i would just let it warm up before i drove it, but like he said check the choke adjustment, and i have no idea why you would put that on a 350 it will have no power, and fuel mileage will be bad, but you gotta do what you gotta do to save a few bucks now days. but hope you get it fixed