Quick lesson,
Your current dizzy has BOTH mechanical and vacuum advance/retard, on top of the advance given by the weights being thrown out due to centrifugal action and so rotating the plate they are attached to(and thus the ignition pickup/position), it has vacuum in addition, so it can advance even more that that which the weights give it, it does this by using the high vacuum created under cruising conditions, put your foot down the vacuum depletes and the amount of extra advance given by this for mpg is lost.
Some cams can play havoc with the advance retard plate(on which the pickup is mounted), causing it to bounce around, so we get rid of this bit, and let it rely solely on the mechanical advance retard which is purely speed related(centrifugal force).
All you need to do is disconnect the vac pipe from the dizzy, and plug the pipe so no air leaks.
A lot of people remove the vac can(capsule) on the side of the dizzy body, and fix the plate in position by a screw, spot weld etc, but the vac can if left will hold it static so doesn't need removing.
So long as you know for a fact you have enough valve/piston clearance the valve timing needs swinging, the best way and only accurate way to do this is on the dyno, where you can say dial in 5 degrees retard for example and see what the power does, if worse go the other way, my guess is it needs retarding, 1 degree isn't even worth doing, but the op should know this, as a rule up to about 4 degrees isn't going to make a colosal difference on your spec of engine, I'd speak to the cam maker as i have no idea if you have enough clearance or not.
If you contact aldon automotive, they may well have a ignition curve to suit your dizzy and cam, which can save a lot of work/cash, as no doubt your op won't be happy to alter ignition curves by bending stops etc, unless old skool!!
tabetha