Most likely, the valve cover is leaking. I can't think of any sort of oil passage between the block and the head that's anywhere near that side of the engine. Check to see if the bolt hole in the valve cover right above that area has a dimple in it that's not allowing the valve cover gasket to seal properly. They almost always get overtightened and distort the sheet metal, and oil leaks from ahead and behind the bolt hole since the gasket doesn't get compressed properly. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
We have a UV light and an oil additive that makes the leaking fluid glow bright which in turn makes tracing the leak back to the source much easier. This system was originally for a/c systems but now used for anything liquid. Takes just a tiny bit of the additive. google uv oil leak detection and get lots of hits.
As others have suggested, it may be the valve cover gasket. If we had detailed pics of that area.........
Craig
My '50 Chevy 3100 5 window, '62-235cu, 3:55 rear My truck ....... Respect The Rust If I'm not working on my truck, '65 m00stang or VW camper, I'm fishing with the wife or smoking Salmon.
You should be able to see it if it is the valve cover leaking. Now sometimes the fan can blow oil from a leak say under the front of the valve cover, down along the side. If you suspect a head gasket problem, I would suggest re-torquing the head bolts.