AND, if you look at "Zerogas's" 6 posts, 5 of them mention HHO? Methinks I know why he's here, pedaling this scam.
I've actually done a bit of reading on this Ron, there is considerable risk of damage. Since it runs and actually is able to ignite such a lean mixture, and without significantly retarding the timing, peak cylinder pressure occurs BTDC (BAD!) but also causes cylinder temperatures that are excessively high. So yes Ron, your thoughts were correct!
Back in the late 70's my stepfather fell for the cow magnets around the fuel line scam. I had a good laugh at that! The jerk also made me install headers and free flowing exhaust on his 460 (7.5L) powered F150 that was otherwise stock. With the factory jetting and OEM exhaust it was running pretty lean to begin with. I asked to do a mild rejetting of the carb to compensate for the VASTLY freer flowing exhaust, he refused, he didn't want to burn more fuel. For his miserly insistence, he got burnt valves and a vehicle that needed oil added as often as it needed gas . . . and that was with a 460 gasser, they could guzzle fuel! Towards the end, it was burning a quart of oil every 150-200 miles.