DS rockers not getting oil...help

Hey guys! I just got a new toy for my collection and am super excited to start diving in head first. Car is a 70 dart w/a 318. Was told it needed a "tune" (whatever some people think that is nowadays :P) and am expecting the worst. Just towed it home and started opening it up. Engine had some knocking, and upon removing the valve covers I saw that the DS doesn't seem to be getting nearly enough oil and the oil pass shows some rust colored gunk at the top of the rockers. PS looks to be fine. Is there something that might be blocking the oil from getting to the top of the heads? I am seeing if there is anything I can do before taking the heads off and having them redone...of course, I am preparing myself for some bottom end issues as well. Enlighten me, please!

Here are some shots of the DS and then PS w/the covers removed so that you can see just what I'm talking about.





Thanks in advance!