hi mike just chiming in on this thread i have a evo 100 put on the plane but one thig horisson never mentions is that the stock exhaust WILL NOT WORK. you have to buy some sort of pitts style muffler and chop up the cowl to use that motor. bisson makes the only inverted one ive found for the evo.100. #5611 the other alternative is a coustom one by JTEC. or DAVE BROWN horisson should tell people that before recomending this motor. thanks steve.