TO30 Oil line

The Continental engine is bad about loosing oil to the rocker arm shaft. I think the problem is the corks in the end rot out, then the oil pressure at the rocker arms falls and they drag and break off the pin that keeps the rocker arm shaft from rotation. Once that pin is broken the shaft rotates in the towers and shuts off the oil passage in the end tower from below. And then things get worse. If in your rebuild you have cleaned out the passages so that there is oil to the rocker arm shaft for sure and that the ends of the shaft are plugged (I just made a new shaft that uses 7/16-20 set screws for plugs) then the pipe outside shouldn't be needed. There's an extra hole in the rocker cover probably from it. But the thing to make sure of is that there's oil from the internal passage. It may need roto rootering with wire and brushes to make oil rise to the rockers.

It could be that deposits from using non detergent oil has blocked the oil passages, then the other stuff happens later. Some of the early ford ('58+) overhead car engines had the passage clogging problem. It was in their lower cost engines for compacts, not their first overhead valve engines. At least not in my experience.

Gerald