Hy WillH, the HEI uses all electronics to replace the mechanical switch [points], you get a super consistant high voltage spark. That means longer intervals between tune ups, better fuel mileage, easier starting, and in general less ignition problems. Once you do a tune up with a points type distributor and set your dwell and timing, the rubbing block on the points will wear and cause your dwell and timing to move, if you don't believe that, then set everything up, and then drive the vehicle for a week and check everything with your dwell meter, and timing light, you'll see how much things have changed. Basically HEI is a much better ignition system, and so are the points eliminator kits, such as the Pertronix kits, which I have installed many of, hope that helps.
