So is it safe to say that since the disrtibutor vacuum line connected to the carb (2GV) up near the fuel inlet that it used port vacuum? I think i have read that if the vacuum tap is below the throttle plate then it is manifold and if it is above the throttle plate then it is ported vacuum.
Demon carbs have both "taps" below the throttle blades or more at the same level. One goes to a ported source well above and into the venturi. The other feeds through channels to the underside of the carb to expose the manifold vacuum.
It is easy to tell which is which. Ported will not show vacuum at idle. Manifold will.
If you are trying to figure the rate your vacuum can runs at just hook a handheld vacuum pump straight to the vacuum can. Let the engine idle and check the timing. Then, slowly increase vacuum with the handheld pump and plot the curve of the can using the timing light.
Nobody should need to take their distributor to a shop to have it dialed. There is no magic in a distributor, it is a simple device. You need a timing light, a handheld vacuum pump if you have (vac. advance), an advance curve kit, and a tach. Just plot your curve every couple inches of vacuum for the vacuum advance. Plot your mechanical advance curve above idle based on RPM and degrees. From there it is just a matter of making sure the internal parts are working right. Make sure nothing is sticking and that the weights are swinging out all the way and returning (this will show up on your plotted advance curves).
I like a lot of initial advance. I run 20o with 14o mechanical and @16o ported vacuum, all in by 2,500 to 3,000. I like the curve to start a few hundred RPM above idle. Make sure you don't use up any of your mechanical advance at idle. Depending on how close you are, you may be into your curve in park, but make sure you are not in drive.