Bruce ( Shrinker )
A functional vac adv is the single most effective camshaft tamer you can get.
load sensing spark advance is extremely important in achieving great driving standards.
When i tune engines i make sure that the spark strength is as strong as i can get it,this includes changing coils and ignition types,alternators (which i monitor as we drive - a lot of the time they get changed) etc..its such an important part of creating a strong flame kernal in the cylinder.
I always change plugs and dress them so that they fire as good as i can get them to fire.I change the gap to suit the vaporization of the carby,if i get the carby good i can then try bigger gaps.Bigger gaps engage more fuel molecules and if the amp energy is strong over the duration of the firing then all sorts of running standards change.If the way that the carby gasses the fuel is poor then the gaps become very critical.
Once i have got these aspects in place i then use a timing curve that suits.
Vacuum advance is a big part of it all.
Its generally in that order that i start the process.This works good for me.