The engine in your photo is either a 216 or a low-pressure 235, and the oil line you're referring to goes through the water jacket and supplies oil to the rocker arms from a fitting under the sheet metal side cover on the passenger's side of the engine. There is a roughly triangular-shaped sheet metal cover behind the exhaust pipe called an "oil distributor" that controls oil flow to that line. There should be a 1/8" NPT (pipe) plug beside the oil distributor that is the attachment point for the oil filter outlet line. Oil from the filter joins with the flow to the cylinder head after the oil distributor does its thing. The purpose for the oil distributor is to restrict oil flow to the cylinder head until pressure at the crankshaft reaches at least 15 PSI, something that happens only at highway speeds on most spray-oiler engines. Plumbing the oil filter output to the head results in at least a little oil reaching the rocker arms, especially on worn out engines with very low oil pressure.
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!