The .40 gasser engine is a NV-Engines GX40 RC engine. It uses a OS P3 ultra hot glow plug. But the insides of the engine are not the same as the .40 glow engine. They changed things on the inside. Also the engine requires Klotz Benol for the oil, nothing else will work.  But the little engine does run like a champ, and is quite powerful too. I have one and I have been flying it a lot too.

http://www.nvengines.com/

I do not think that we could get another different engine to run this way, as the NV Engines GX40 uses a ceramic like coated cylinder that can handle higher engine temperatures and I think that is what it uses to take advantage of the situation, along with subtle porting and compression changes. Plus they have a carburetor calibrated for gasoline too.