fun,
Are you talking about the 'desired' point being the Lycoming specified leaning (50 degrees rich of peak EGT) or tuned leaning (50 degrees lean of peak EGT)?
Any leaning is good, but it really depends on the engine - injected engines tolerate vicious (aka GAMI tuned) leaning far better then carbed ones - the O540 vs the IO540 for instance
Speaking of IO540, I think he can explain this far better then I
