[Woodz428]

Semper Fi,
I'd have to guess there is something weird about the serial #'s you are using. The earlier cars are the more flat ones and the later ones have the taller arch. This was done to make the 460 based engines fit easier. A few pics of the 2 tags would eliminate the issue with the numbers. It sounds like 1715 may really be 715. Since I haven't read all the posts, were both the cars bought new? If not, had any damage been repaired? What dates were they purchased, if new??