Roger,

Should I take our 172 N above altitudes where the POH says max power is 75%,
put the throttle all the way in, lean till it gets a bit rough, and then
enrich until it's smooth? As long as CHT and oil temps remain in an
acceptable range, can I then cruise along confident that I'm getting there
fastest and getting the best life from the engine?


Well, are you getting more than 2400 rpm at 75 percent? I don't think so. So
you will be WOT at those altitudes anyway, right?

--
Thomas Borchert (EDDH)