The early full pressure engines have the short line that only goes from the back of the pushrod chamber to the oil connector. The spray-oilers have a line that runs all the way through from the driver's side at the oil distributor, through the water jacket. Usually, cleaning the line under the pushrod cover doesn't do much good. The restriction is in the block passage around the rear cam bearing. I usually use a high pressure air hose to blow the crud out of the block passages while I've got the oil line removed.
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!