How do I know if the vac port is reg or ported vacuum? Just attach a vac gauge and if I see 14 inch at idle I am OK as a non ported vac?

What is ported vac used for? (synchro maybe like a crossfire TB?)

1995 7.4L TBI.

Or the F Body family of TBI. Thank you.

I will guess is "ported" just is very small amount of vac?

 

Ronny Ported engine vacuum is available above the throttle plates of a throttle body or carburetor. In the past ported vacuum was used to advance ignition timing on carbureted engines when the throttle is opened above idle position. To answer your question hook-up vacuum gauge to suspect port and slowly move throttle from idle. If vacuum changes from 1-2 in-Hg to say 14 in-Hg you have a ported vacuum. If it changes continuously, but remains more or less the same it is manifold vacuum port (i.e. on the back side of throttle plates) //RF