Not sure about prop factors but the increase in prop diameter will be offset a bit by the decrease in pitch. it it were me... I would spend the few bucks for the correct break in prop as one of the things to ensure a happy engine down the road.I will say this.. I have the supertiger 40 you do and it takes some time to break in. I had some flameouts on takeoff after a couple tanks and followingdirections on theengine stand... but once broken in it runs like a swiss watch.