I concur about the saito. I have a Giant Scale U-Can-Do with an inverted Saito 150. I do have a 2 ounce Saddle Tank mounted left fuse side directly behind the cowel to prevent air bubbles, etc. I do every 3-D manuver you can dream of and I've never dead-sticked!!! The Saito is simply ROCK SOLID. One of my flying buddies has a 2 stroke in his 60 and it has dead-sticked inverted twice in the last dozen flights. He is going to install a Saddle tank so that may help. If your curious about the saddle tank, I will swear by it! every time I finnish flying, the saddle tank has about 5 tablespoons of air in it. That would've been air going to the engine other-wise. The 4-stroke works VERY well with this plane... ONE LAST IMPORTANT THING! Be VERY sure to add some bracing to your tail. I had my rudder stab completely shear off on the fith flight. The rudder stab is contructed from soft balsa and will not take the forces given to it unless you have some tail bracing. If you look at my profile, you can see the pics of my Giant U-Can-Do.