Hi.
It can be done on either electronic distributors or in point type ones. Both have the advance springs within. The standard distributor has a mechanical advance mechanism which is controlled by two small springs. The springs are located under the breaker plate or points plate in point type distributors. On electronic ones under the pulse generator plate.The mission is to alter the advance mechanism.
Perhaps a little complicated to begin with. Perhaps that work will be needed with a cam and more performance mods. At this point, just to mention it, there is work that can be done to make your stock dizzy perform like a aftermarket one, within the constraints.
First step in upgrading the ignition system is a better coil, Accel, MSD , or the available ones in Australia, good ignition cables and later on distributor work.