Clean, properly-gapped plugs fire at less than 10KV. The other 40K available with a HEI system is for lazy owners who refuse to do preventive maintenance on a regular basis. The whole concept of HEI was to satisfy the government mandate that emission control related components had to last for 50K miles without maintenance. It's possible to cut the ground electrode completely off a plug and still fire it with enough voltage available.

People with something to sell have a habit of lying about what's necessary, and they have just the thing to solve the problem for people gullible enough to open up their pocketbooks.
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!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!