I've got a twist and use a saito .72 with a 1x6 or 13x7 apc prop. any larger four stroke will definitely be overkill. a .61 2 stroke would probably be too much. mine wieghs almost 6 pounds, but will still hover at half throttle with either prop. btw, i use 20% nitro fuel. mostly just a preference. better idle and runs cooler.