Maybe I'm using the wrong term.  This vent is located
on the center housing very near the filler tube.  I
believe that there was a tube on the engine originally
that went from it to a port on the filler neck, but I
very well may be wrong. 

Attached is a pic of the port I started using when I removed the filler neck.  Is this the one you're talking about?  This is open to the same area as the filler neck, so you can use it, or the filler neck, but don't connect them together, or you have no vent. 

>I don't know, but it is near the top of the cowling.
Originally I didn't have anything hooked to it at all,
but after hearing about some others have oil
discharge, I hooked up a piece of tubing to it and ran

That was almost exactly the situation I had.  At first, I had a little PCV filter directly on the oil filler tube port, and never saw more than a few drops of oil collect in it.  Once I "wised up", I put the vent line on, and ran it to the cowl exit.  Over the next few flights I proceeded to lubricate the belly and tailwheel.  So much for wisdom :-) 

I now run the yellow hose you see, into a much larger clear hose, with a valve on the end.  The vent occurs between the two hoses, and any oil would collect at the bottom of the clear hose where the valve is.  None ever collected, well, until I trashed the engine.  I can tell you the vent works well when you trash the side seals :-(