I have been tempted to get one of those engines too. I was thinking of the little ducted fan, plane and engine with tuned pipe. But unfortunately they wouldn't ship the plane though.

I strongly suspect that the aero engine is a converted car engine. They had three different heads for the engine. Plus there were pull start versions and car carbs, etc. The ducted fan version used car head, a pull start, and a car carb on it.