I've only seen one of the Evo's in use, it seemed to run fine for its owner, and he was happy with it. It looks like a glow engine with a gas carb on it. the exhaust is out the side, and I'm pretty sure Slimline or Bisson would have a Pitts style muffler for it. As far as the conversion engines go, there are a lot out there, bur most seem to have a side carb. try Carr Precision's website, they have several different brands available, and several ways to go. You can send them your engine and they will convert it for you, or they will sell you the conversion parts and you can do it yourself, or they will sell you an already converted engine. they even have a 4-stroke Honda engine available.