unless the c5's were made in austrailia and shipped to japan to be put in cars......i don't think IMO the numbers mean where they were made....they are just different versions of the same engine (somewhat) just given a different name and different build ups....could be wrong though...:dunno: would be kinda hard to differentiate the engines if some of em had 170hp, some had 190hp, and others had 200 hp but all had the same name ya know?