Does anyone know what changes ski-doo did to the 1998 mach1 engine vs the 1999 engine. I know there were some changes on the crankshafts and the cases but what were they? Can you update the older 1997 and 1998 engines to the newer 1999 and latter design? I blew the engine in my 1999 mach1 and need another engine to start the rebuild process. So far I can find 1997 and 1998 engines but I am not having much luck finding a 1999 or latter engine.