OP, remove the line from the vacuum pot on the distributor and suck on it, see if it holds a vacuum. if not replace it. if it does, plug port and leave line off, then set base timing and 12*.slowly rev up until you finish the mechanical advance curve (probably end up about 28* at 2750rpm or so). then plug in the vacuum advance and rev it back up to that rpm and see how much the vacuum advance added.
so then you will know your initial timing (12* Adv) total timing (x*) and the rpm you get full mechanical Adv. lastly you'll know your how much vacuum advance you have.
what you want is something about like this, 10-14* initial, 30 total by 2500, 50 with vacuum advance.
