Chevrolet K-series trucks didn't have a system specifically called "High Energy Ignition" in the way some other manufacturers did. Chevrolet used various ignition systems over the years that improved spark energy, but there wasn't a single, branded "High Energy Ignition" system applied across the board. The improvements were gradual, incorporating things like improved coil design, electronic ignition (replacing points), and eventually electronic control modules.
To pinpoint a specific year for a significant jump in ignition performance, you'd need to specify what you consider "high energy" in comparison to previous systems. The introduction of electronic ignition was a major step forward, but its implementation happened gradually across model years and engine types. You would need to consult a specific year's Chevrolet truck repair manual or parts catalog for details on the exact ignition system used.
