High performance is all about horsepower. But even the ultimate in heads, compression, cam, and the rest won’t make power if you can’t light the fire. Ignition systems don’t make horsepower, but a ...

Introduced more than three decades ago, GM's HEI ignition system has capably powered tens of thousands of vehicles over the years. The setup has remained popular with performance enthusiasts to this ...

This GM HEI has the typical gummed-up mechanical-advance mechanism. Note the corrosion on the advance-weight pivot pins (arrows) caused by voltage arc-over and lack of lubrication. Brad Urban at The ...