The pertronix upgrade and the 40kV coil is the cheapest upgrade, if your original distributor is tight and in good shape.
It uses the same magnetic hall-effect sensor/trigger as the HEI or other magnetic point dizzys, which can handle 50kV.
Installation takes only minutes on an already installed and tuned distributor.
Mallory offers two versions of point-breaker-less ignition - light sensor or magnetic sensor, as a straight drop in for the early 6s. They also come with adjustable advance. No grinding required.
All this has its price, but these units are new and not decades old used and refurbished giving random fitting problems on a case to case basis.
