A couple of guys have Saito 170R3s on theirs and that's what I have for my kit. It is rated as putting out the same HP as the Saito 1.20. Yes, this is cutting it close but those guys say theirs flies okay. Not really great, but good enough. I need to put the engine on something and this is what I have waiting to build.

Otherwise, I would say put something bigger on it and that is getting into gas territory.