A turbo engine means it uses a plug that is flush with the bottom of the head, and the threads are tapered like \ / instead of l l. Not sure about the button, and I believe that a turbo crank means that it has a fan blade looking thing indented in the end of the crank that sucks air in to go threw the ports into the chamber. Do a search on "engine moding" and you will find links to pics of the crank I'm talking about.