Basically yes'

But the application may not warrant it, some engines would work in large boats better than aircraft, and a stripped down snowmobile engine would fly a ultralight or one large scale model.

some engines have the ehaust forward, may not be a good choice and others have too much weight to be trimmed.

a machine shop or a lathe can do wonders for making adapters for all most anything, but whether or not its worth it???

Hope it helps"