+1 on the valve replacement. At 2000 RPM, each one of those valves is opening and closing 17 times A SECOND! Are you sure you want to count on something produced in the 1950's or even 60's doing that reliably?
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
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