Rear Main Seal

If you do a rope seal correctly, they actually work well.
Ok truth? It took me a couple of tries,lol,
But in those days I was taking the 367 out every September long, and swapping in my 318 test mule engine for the winter. So then I would take the 367 apart over the winter looking for issues before they spoiled my next summer. The engine usually went back in on May-long. Most of the gaskets were the re-useable type, so this wasn't costing much more than time.
The first rope seal was a disaster; it did not survive the install. The second didn't pass the pressure test. The third time was a charm. Fourth and fifth,also good. Now it's been in there since 2004/5.