The corrosion on the face is not a concern but obviously the corrosion on the cylinder seat is. This type of corrosion is the result of using straight water and/or a system that cannot hold pressure. It also happens to systems that regularly leak and have coolant added on a regular basis. 
Contrary to rational thought regular additions to a cooling system is not good. Every time fresh water is put into the system so is fresh oxygen. Think of a house baseboard or radiator heating system. No additives are used (normally) and the plumbing and boilers last for 30 years and more! Why? Once the system is charged and the oxygen and other corrosives are used or purged everything is good. If a leak develops and the system adds water on a regular basis then corrosion will begin and then boilers fail and baseboards begin to leak as the damage progresses. This appears to more erosion from coolant vaporization than corrosion. It happened hear the cylinder spigots and that is the hottest part of the engine besides the piston and combustion chamber. That spare engine was not as good as you may have thought. 

Dennis

       

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of J Stewart
Sent: Saturday, February 15, 2014 6:10 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Head Pic

I think I already know the answer to this, but this was the spare head I planned on using on my '85-til I saw this. Is this now a paperweight? I'm thinking it's shot. This is where a lower stud passes through just below #2. More pitting right next to it. The head that came off is razor sharp around the edges, so it is looking like it will be going back on, but it has a chunk missing around one of the front exhaust studs. Hopefully I did this right, I did make it public.

https://plus.google.com/photos/106005770038938396483/albums/5980762725498000049?banner=pwa

Jeff Stewart