I just started tearing down my 52 V8 , it looks like it was a real oil burner , most of the valves were not sealing good and oil/sludge was knee deep under the intake manifold . I got the valve assemblies all out , good fun there! And then when I pulled out the lifters 4 of them were badly pitted from the top to were they come up to open the valve . I didn't see any water in there to rust them ,they look clean but pitted . What could cause this? Is it something to worry about? Some of the valve guide were worn , I could wiggle the valves a bit. Engine was never stuck like most are ,turned over ok, just some of the vaves were stuck ,PB blaster ,time and a rubber hammer loosen them up fine. tony

 

Pitting of the lifter cam face is usually caused by acidic oil. Previous owner probably did not change oil often enough.