stotman,
Ahaaaaa! Now I can see what's going on in the first picture. You have successfully twisted the rocker supply line off. Don't feel bad, it's actually soldered to the fitting, but you wouldn't know that unless you did a bunch of research first.
That line passes through the water jacket from the drivers side. It pops out under the exhaust manifold and connects to the oil distributor, which has a steel cover and a line near it...take a look, you will see it.
You will have to buy the kit to replace the entire line from oil distributor up to the center oiler. That is the 'main vein' for lube to the upper end. There is another curly-cue piece of copper tube that comes out of the center oiler and just dumps into the head area.
That line is the overflow and isn't attached or plugged into anything. The picture Hoyt linked shows a later version with its supply coming off the rear cam bearing. In that picture, you can see the oil distributor valve on the right hand side of the engine. Your supply tube actually passes through the water jacket in route to that valve.
The tube must penetrate the water jacket, but be able to seal it where it exits...hence the factory soldered fitting on one end.
Are you confused yet?
EDIT. Look at this link.
http://chevy.oldcarmanualproject.com/shop/1938/38csm149.htmlStuart
