vacuum advance ???
 

got really tired of playing with my Holley carb, so i bought an Edelbrock, no particular reason, just frustrated..



anyway, it has two vacuum ports on the front for the vac advance on the dist.


one port is for timed vacuum and the other is for full vacuum...


which do i use?? or does it matter??

Yes, it matters a great deal. Ported vacuum and manifold vacuum are the opposite, so if you hook it up to the wrong one, your timing will advance when it shouldn't, and won't when it should. The ported vacuum (the one you feel get stronger as you open the throttle) is the one for the vacuum advance.

Take care,
-Chris

thanks chris