Just wanted to update this post. I completely disassembled my rocker arm assembly, cleaned everything, cleaned out the inside of the shafts (which were pretty dirty), and made sure the oil supply tube behind the pushrod cover was clean and clear. I have the hollow head bolt in place, too. Started the engine and ran if for a while and it seems like I'm still not getting oil to the rockers. No oil flows out the overflow tube up top. I pulled the threaded plug from the side of the head and it's completely dry. No oil flows out.
One thing I noticed. I used assembly lube when I put everything back together. It looks like oil is pushing up through the little holes in the tops of the rocker arms--kind of coming up through the assembly lube--but that is only happening on the rear half of the shaft.
I looked at a video someone posted here recently and you can see oil dripping down off the rocker shaft. Mine is definitely NOT doing that. Since I'm unfamiliar with stovebolts, can anyone tell me how much oil I'm supposed to be seeing? I poured some clean oil over the rockers before starting, just to make sure they'd be lubricated until the oil got up there, so I don't know if the oil I'm seeing is what I poured at the beginning or stuff that's been pumped up there.
If I wanted to use the bypass option and run a supply line to the threaded plug on the passenger side of the engine, can I tap into the lines going to my oil filter? Here are pics of those lines:

One of these lines goes to my oil filter, the other goes to the oil gauge:

[IMG]http://i7.photobucket.com/albums/y261/bohon/56%20Chevy%20truck/VR004.jpg[/IMG]

One of the oil filter lines:

[IMG]http://i7.photobucket.com/albums/y261/bohon/56%20Chevy%20truck/VR005.jpg[/IMG]


1956 Chevy 3200