Great diagram. I agree it is all about the setup and having the dizzy mech-advance-curve, vac-advance-can, vacuum source and carb(s) working together as a system.
I realize that a lot of modern cars have ported vacuum designs - but as I understand it - these designs involved de-tuning previous generation systems to meet emissions:
Colorado Corvette Crazies including severely retarded initial timing.
The challenge I have always had with sticking to the compromise of a 'ported' vacuum setup (when hot rodding) is the amount of initial advance that is required (especially when camming). In my experience it makes for hard starting when the engine is hot and risk of pinging at WOT under load.
