Posted for Susan Brunner <n98pb@sbcglobal.net>:

I attended the  APS last May and left with the 14.7 number from George Braly.  When LOP the controling factor is the fuel flow in determining HP.  Park your engine and manage the FF.  14.7X16.5=242/350=69.3%.  I run my engine at this setting and have found it to be smooth with the prop at 2400RPM and a MP of 30".
 
Hope this helps.