ported vacuum

[denguy]

What is meant by "ported vacuum" and where would a ported vacuum source be on a carbed engine?
thanks

[Movin]

Inside the carb the throttle plate in the closed position the ported vacuum
orifice will have no vacuum as it sits on top of the throttle plate. A idling
engine will have full vacuum under the throttle plate. When you open the
throttle just a little the throttle plate will rise just above the ported vacuum
orifice and give it full vacuum.
Both FI and carbed engines can have this. On a carbed engine this feature
is desirable for vacuum advance as properly set up it makes a nice responsive
throttle.
The ported vacuum source will originate on the primary throttle bore on the
top opening side of the carburetor. It can be plumbed anywhere from that
source.

[denguy]

Thanks, Movin.......

what would happen if you ran a vac line from a port down on the intake manifold itself over to the upper vac advance port on the disty?

[Movin]

This might be appropriate here. A TSB from Ford. This is the way they want it. At
high elevations a modified approach is needed.
There are 3 more, two for 89 and two for 88 california and federallies