I really appreciate the articles. I understood the reasoning behind the use of vacuum advance, but I never understood why base timing was so retarded on engines when we know they like more initial timing. The emissions info clears it up. I still see no reason to use ported vacuum for the advance.

A test that I want to do now is hook up my mighty vac to the vacuum can and see when full vacuum advance is achieved. Interesting. I am assuming that the adjustable cans adjust the amount of advance, and not how much vacuum it takes to get full advance.