Q-Jet Question/78 vette

[antique78vette]

Hello there C3 partners,

A newbie here at this site........Got a few Q-jet pix I'd like to share with the readers with respect to a mysterious capped off port. I've been all over the Q-Jet and intake manifold and find no unclaimed vac lines etc. Would like to know what the port is/was used for and any thing that may shed some light on this mysterious capped off port.

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[Evolution1980]

First, Welcome to the
Be sure to stop in to the New Member Introduction section and say "Hi!"

As for your carb question, I'm looking through my service manual for the 1980. Should be the same carb. I'll let you know if I find anything. Otherwise, someone else will likely chime in here.

 

[Evolution1980]

Checking in the manual showed it in the pics, but it wasn't labeled. Since GM used the same carb base for many different models of cars, they included a bunch of vacuum hookups for just about every conceivable connection that a car may need. If your car is operating as expected and you've got all your vacuum lines accounted for, that's likely a factory capped plug.

 

[mkapp7879]

That's the port that SHOULD go to the distributer vacuum module.
Where's the hose from the distributer go to on the carb?

 

[Vette79]

That's the port that SHOULD go to the distributer vacuum module.
Where's the hose from the distributer go to on the carb?

Correct. Ported Vacuum but the Vacuum Advance for the distributor functions better connected to full intake manifold vacuum. Ported Vacuum was for emissions.