If I remember how track did their naming convention, the 9 series meant top shelf, 10 meant the intermediate diff, and A meant Angular. Looking at the core shape and numbers, a Black Ops would be closer than the HB and WHB, all things considered. Haven't thrown our STC yet, so I can't comment on that. HB will be a little cleaner and more lopey, but more hockey stick shaped at the end of the pattern.