There are in my opinion at least 3 advantages to a well designed HEI system (and I do not include Pertronix in this at all): more consistent spark, hotter spark output and your coil will run somewhat cooler and last longer. After the startup and consequent inrush of electrons, amperage needed by the coil will decline. Added to that the HEI scheme will let you run a wider gap on your spark plugs, your plugs will last longer and if your results match mine, combustion will be improved...it is a more energetic spark, after all. A leaner running carburetor can be used, also. That ties in with the whole idea behind the HEI change...leaner fuel is by nature less optimal from a combustion efficiency standpoint and the HEI system was effective in burning that fuel and causing less airborne pollution. You may notice one change if idling your truck in a garage. It won't smell as bad because you'll be burning more of the air/fuel mixture...which some will say extends the life of your exhaust system (although I think relative humidity and where you live is equally as much of a determining factor). You will also notice hotter exhaust gasses...holding your hand in front of your tail pipe things are going to feel hotter back there. I'm not saying all the smell of unleaded fuel will disappear. It won't but it certainly won't be nearly as overwhelming.
I'm not against points at all...not in any way. They're just fine and I am always trying to think of ways to improve their effectiveness. But just like HEI there are some limitations. I am and have for a year been considering a coil-on-plug system for the Stovebolt engines. What's the advantage there? There are a few. One is that each coil will fire after a longer resting time interval...a big positive. But unlike HEI which can easily be adapted, this is more of a technological swamp. And I'm not convinced the old inline 6 will benefit from this technology as much as I had once hoped.
