1969 Dart Street/Strip (Re)Build

Sounds like my luck. Two times the builder did rear main seal and couldn't get it right. I decided to do it myself and that's when I discovered other builder issues. Anyway the seals will never work unless the seal it self sticks out past the machined surface. The last one wasn't even close and silicon is not the answer

This is the second rear main seal that's been put in it so I'd hate to think that would be the culprit but like you've found, it can happen. It could also be leaking down from the valve covers. I seem to notice oil around the rear corners now and then. Either way I'm sure I'll get it all figured out.