Ignition timing is easily the single most important tuning adjustment on an internal combustion engine and yet the concept of ignition curves continues to be elusive for many enthusiasts. Yet all it ...

Reliability, a simplistic design with many interchangeable components, and heavy support by OE-replacement and aftermarket manufacturers alike makes GM's HEI among the best executed distributor ...

When General Motors introduced the High Energy Ignition (HEI) distributor in the mid-1970s, it was revolutionary. So much so that it still has a strong following among today's hot rodders. Like other ...

Let’s start by looking at the evolution of the GM High Energy Ignition (HEI) system. This system became available as an option in 1974 and was standard in all 1975-and-later vehicles, with the ...