At normal highway speeds and engine loads, (even heavily loaded commercial engines) there was no measureable improvement with HEI over point ignition, as long as the plugs were relatively new and clean. As the plug gap increased due to wear and/or neglect, the increased voltage capability and the long-term reliability of solid-state coil triggering became a factor. Conventional ignition points simply could not meet the artificially-imposed "50,000 mile service free" mandate in the Clean Air Act, which was the only reason HEI was developed in the first place. Operation of a General Motors HEI system above 5500 RPM required major modifications to the distributor to prevent spark scatter and other problems created by speeds above those the HEI was designed to run. I challenge anyone to show me documented evidence (not opinion) otherwise.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
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