Thank you for the quick response. I've never had the engine apart in the 7-1/2 yrs I've owned it, aside from removing the valve cover, and that was just recently. Based on the information I have, it was rebuilt roughly 13,000 miles ago, which I'm guessing based on my ownership was probably at least 15 years ago (or more). There's no visible sludge in the head, so I'd expect the internals to be relatively clean too.
I'll try to clean the holes with wire. I'm thinking I might be able to cover/plug the back holes to force the oil more to the front to help clean out the holes. I guess if that doesn't work it may be time to tear the rocker arm apart.
