I have just downloaded the new Beech 18 volpar and other than re-arrainging the avionics I have decided to try an engine upgrade by modifying the Beech 18's aircraft.cfg with the engine data from Milton Shupe's Howard 500.  I will post the results after I do the flight testing although I am suspecting I could end up with over speed and over stressed during cruise flight and such. It is a big power increase. Wish me luck.