A few weeks ago I asked what this oil line was for, and I found out it was providing oil to the rockers, because the oil passage from the engine block was probably blocked. I pulled off the head and found the engine block's oil passage . It turns out that the head DOESN'T have the same oil passage . Mystery solved!

Where can I find the correct head and how much should I expect to pay for it? If it's too much, I'll probably just replace the "mystery" oil line with better tubing, and replace the head when I need to rebuild the engine.

Just curious, what engine/year would this head come from? Maybe from a full flow engine? I'm finding out that the previous owner did some questionable things just to get the truck back on the road.