Based on what I read in the WERA Rulebook, it appears that the Kawasaki ZX-6R (636cc) is legal in both C Superbike and C Superstock classes. Did I interpret it correctly? Thanks, mar.
According to the phone call I made to the AMA, they stated that it is NOT a legal bike in any of their classes.
And you would be wrong there as well. FUSA allows 640 in sportbike and 660 in Superbike. The AMA is only one that does not have a class for the 636