Thanks for the quick reply. Let me see if I have this straight. So, they are shells, with casting numbers that indicate the "original internal build" (M15 or MN7), only? But will never guaranty "integrety" of the MN7 (Gear ratio 2.93/sprockets, Diff-HD, and front Passenger side drive axle) are still present? And Vise/ Versa? If still correct, and that being said, can I know, if the "casting (only)" started out as an MN7 or M15?