Aftermarket block street strokers.

My milodon s/s pan has a huge washer on the outside which I noticed rides on the pan rib and caused a very annoying slow leak. That's a soon to be fixed project.
Yep, common problem with Milodon. They don't pay attention to where they punch the holes so sometimes the washer ends up on a rib. When they make an oil pan for external oiling they should use a different rib pattern. Very simple engineering fix but they have never made the fix in 50 years of production.