I believe the 85mph speedos were unique to the U.S. for legal reasons. I think they started putting those in '82 or '83, and I guess they stopped in '84, because my '85 has a 120mph speedo...

I do know that switching from a 120mph to an 85mph is a difficult transition, because 60mph is at the same place on the 85mph unit as 80mph is on the 120mph...