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 ...

Otherwise, HEI drops right into any vintage Chevy small- or big-block without breaking a sweat. Originally, the HEI system was fitted with a four-pin module. By 1978, it had a five-pin unit.

Car Craft tales you through the steps of how to convert a Ford or Chrysler ingition to a GM HEI for a high-performance, more-efficient ignition.