Need some vacuum connection help...

[John]

Both the large port on the back of the carb and the port on the intake manifold are "manifold vacuum" ports which you want for brakes, transmission, Vacuum advance, valve cover, etc. The smaller ports you see on the carb, one of them is usually "manifold" and the other "ported". You would want the vacuum advance can connected to the "manifold" vacuum. You can check this with a vacuum meter. the "ported" won't have any vacuum at idle and the "manifold" port will.