Be careful here, CP of course knows his stuff when it comes to pumping up an engine. However that engine needs to be mounted in the correct airplane that has a low enough drag profile to take advantage of the small high rpm prop. Example, both these airplanes are .40-.46 size but put a screaming .46 with an 8x8 into the P-51 and you would be lucky to hit 80mph, put the same setup into the Miss Ashley and your good for 160 mph. Put a race designed .40 in it and your good for 180 mph.