I have a recently rebuilt 440 (now a 505) that I have been driving around locally with absolutely no leaks...not even a drop. I've had it on the interstate, but only for a few miles at a time to see how it went, with no issues.

Well, yesterday I took my car onto the interstate (60 to 80 mph depending on traffic) for the first real distance (only about 20 miles) and I'd say at about 10 miles my rear main seal 'totally' blew out. I say that because my interior suddenly started filling with smoke (had the windows up.) Knew it wasn't a fire because it had that burning oil smell.

The leak is so bad that when you stop and look under the car, oil is pouring out almost in a stream, not just dripping out. Sort of in that in between area where you have drops coming out in such quick succession that it is just about a continuous stream, but not quite. And the back of the car was just covered in (clean) oil.

Anyway, I know I have to fix it now, but of all the internet searches, I haven't seen anyone describe such thing. It seems it is usually just some drops that develop over time.

So I am wondering if this is something that 'just happens some times' or if there is some particular cause of this particular scenario that should be rectified before I replace the seal.
I don't want to replace the seal and have this happen all over again because I didn't address some other underlying issue that might have cause it.

Thanks for all the help. YOu guys are an excellent resource to guys like me who barely know what we are doing!!!