When I pulled the valve covers off, I found loose needle bearings in the left valve cover when I was tearing down the top end. This is not uncommon as the bearing cage lip wasn’t wide enough on the earlier needle bearing cages and can fracture. So I replaced all the needle bearings in the heads. Each rocker has a pair of needle bearing cages so there are eight total.
I removed the valves and cleaned the heads to see what I could see. Some of the valve faces are worn down and the valve springs are sacked past the minimum. I suspect the exhaust valve seats are original so I’m planning on having new exhaust seats installed. I’ll also replace all the valve guides, springs and the valves so these heads, which are dual-plugged, should last for a long time.
Here is the link to the write-up on how I did this work.
Here are a couple of pictures from the write-up.