In this months AOPA article on Steve Lackey/Mike Moffitt’s IV-P – In the last paragraph—

Don Gregory was quoted that Charlie K. taught him to operate “10° lean of peak".  Not so!!

This is a typo or a misunderstanding.  50° lean of peak is the standard and benchmark.

 More than 50 is fine if it will run smooth.  But never less.

Charlie K.