They, and the other companies, have really changed their story since 3 years ago. I called ALL of them back then, and they all said "no problem" with SM oil in old engines because of the backwards compatibility. I just wonder how all these "experts" were wrong, since they now all make special oils with more zinc. Should we believe them now? I don't know.

Even Honda uses a special "break in" oil in their new vehicles, and they emphasize not to change it for SM oil for at least 5000 miles. I wonder what they know, and what is in their break in oil.