Don't mean to discourage you but those are cheap engines not worth hopping up. You'll just burn 'em up. Trust me I've ruined quite a few. The tolerances of these engines are much more critical than auto engines and they are much less forgiving of mistakes. This is truly one area where you get what you pay for. A Jett .40 costs about $250 but at 16500 rpm with flawless transition from idle to WFO it is a beautiful thing to behold (and fly). Leave it to the experts!

Max