Ported vacuum?

[Toronado]

So does the ported vacuum out let on the Q-jet
have zero vacuum at idle? All of the ports on my carb.
have vacuum at idle, but less vacuum than the manifolds
outlets. What is a good range for vacuum hg for the ported
outlets on my carb. at idle? I hooked my advance up to the manifold
for a test and it did not make any difference, from it being previously
hooked up to the ported outlet?

[Schurkey]

So does the ported vacuum out let on the Q-jet
have zero vacuum at idle? All of the ports on my carb.
have vacuum at idle, but less vacuum than the manifolds
outlets. What is a good range for vacuum hg for the ported
outlets on my carb. at idle? I hooked my advance up to the manifold
for a test and it did not make any difference, from it being previously
hooked up to the ported outlet?

First Guess:  your idle speed is too high; or at least the throttle plates are open too far.

Ported vacuum should be "0" at curb idle.  You'll have vacuum at fast idle, though.

[Cliff Ruggles]

Agred, a true ported vacuum source should show nothing at idle speed.  Keep in mind that there are several different types of ported vacuum sources on Q-jets.  Some have a very high source location, for delayed/low vacuum, to apply EGR valves, etc.  Some will also have a drilled passage that bleeds off some vacuum and reduces the amount available.

A good ported distributor source will show FULL vacuum right off idle, same as one would see anyplace else under the throttle plates.....Cliff

[Toronado]

Before I got my tach the rpms were to high i think causing the ported to be
open to some vacuum. When I lowered the rpm the vac. gauge showed zero at idle,
so looking good, and running a lot better. before the car would act strange going down steep hill, and now it doesn't want to die on steep hills.
Thanks for the insight on port function and the difference between them.
Now i need to throw a new vac break on it and it running again, of course there still that irritating leak on the front inlet,.....