hhhmmm very interesting......this sounds like the mysterious earl leak my motor had when it was in a family friends coupe....it started when the motor was 6 or 7 years old....oil all over the passenger side of motor and firewall when running at freeway speeds 65-70 or more.

I still have a couple months before i fire that motor up after a rebuild, we didnt find anything off or weird when taken apart, we assumed it was the timing cover, but i will make sure that i put a bolt in that motor mount hole.............good info in this thread