The Pertronix module is a simple replacement which eliminates the ignition points. It is effectively a transistor switching system for the coil controlled by a Hall sensor. It relies on the existing mechanical / vacuum servo system for timing advance functions which can be good or bad depending on your view. They are a simple install and will work in the existing B20E / F distributor.

The Pertronix system has one negative feature. They must be using a bipolar transistor for doing the coil switching because when the module is in the 'closed state' the voltage drop across the module is fairly high. Close to 2 volts as I recall. This reduces the voltage across the ignition coil with an attendant reduction in the coil charging current and potential spark energy. If your electrical system is in good condition and you have good voltage during cranking, the reduction in dwell current may be immaterial. If your system is not in great condition, then the reduction in dwell current may present a problem.

The Pertronix eliminates the maintenance issues associated with the points. It will not enhance performance compared to points that are in good shape and properly set. The Pertronix does nothing to address wear and tear in the advance mechanism which is likely an issue on a 43 year old car.