yep I know, I really don't like these big motors but where we run we started with S/A, then they made it an open class so we had to step up to run with them, we had open animal, then some started running the 390 and 420's so we stepped up to and open 390, THEN some started with the 450cc so here we are with a 500 JAWA, where will it stop.Dude, if it's got the mechanical fuel injection it will run with anything out there even without. More to it than engine as most know later Chuck.