Thanks for help.
Just a question for Big Pistons Forever.... How do you deduce from the tables that above 7k the power falls below 75% from charts? I doubt I'll get that high any time soon from weather here.... But just out of interest...
So, for my flight.... Figure pressure alt, go to corresponding temp. and based on what speed or fuel burn I want, take that RPM and lean for it in flight and I'll end up with that %BHP... Correct?