God says,
Get your vaccuum from the intake, or from below the throttle butterfly of the carb, for everything. That way no hesitation for anything. Get the most snap for your effort.
The only reason we got these "spark ports" on the smog era ('68 and later) carbs is to help eliminate smog (and create a doggier car). Never had 'em on pre'68 stuff.
All '67 and earlier Q-Jets, AFBs, and others are better for performance vehicles because they are richer, have weaker power stage springs, and simpler, stronger idle systems(all provide for snappier response with no stumbles). The later ones can be fixed, with some effort and time.
Try it both ways and tell us what you think. Set your timing the same with no vacuum at distributor. Then hook up dist to either vacuum source and drive it, then hook up to other. Manifold vaccuum source to dist will also be more economical(thats why it was created-by Abraham and Issac Carter (the carter carb boys in the 20s)
