Frank when I got my truck running I too had no oil to the rockers. By the way they look they haven't had oil for a long while. However here is what I did.
I removed the rocker arm assemblies. Then with a very large syringe (2 oz) I tried to draw oil up to the top of the head. Well after a quite a few atempts I was able to do so. My oil passage was just plug with junk. I am sure that is what has happened to yours. Once I got mine unplugged I sprayed some carb clean down the oil passaged. Ofcourse I changed the oil before I ran the truck. This not something that is impossible to fix just takes some time.
Good luck
