Are you talking about the pitting on the intake valve faces?
The material is most likely inferior.

Question- did you run the motor hot before?
Maybe detonation hurt the valves, though it is unusual the damage only
occurred on the intake valves.
Back to inferior material of manufacturing process.

The valves will probably go another 50-100k, but I would replace them anyway
while everything is apart.

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Andrew Martin
Sent: Tuesday, September 23, 2008 11:32 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: resealing heads - found missing metal on top of valves

Since I cannot post photos here...

http://www.thesamba.com/vw/forum/viewtopic.php?p=3307618#3307618

Thanks,

Andrew