There's a 1/8" pipe plug in line with one of the head bolt holes about halfway between the side cover and the valve cover. The port bypasses the internal oil passage, and it was pretty common to see a 3/16" copper tube attached there to supply rocker arm lubrication to an engine with a slow-running or clogged internal oil passage back in the 1960's. The tube was usually routed around behind the block and attached to the oil pressure fitting/oil filter port.
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!