FWIW, the only time I saw a thread about antifreeze and head gasket failures with pictures was over at CF in the ZR-1 section. The author of the thread was "MrCrowley", aka Mike Ebert of EES (Ebert's Engine Service, EES.com). He started the thread to show us what the failure looks like. If I remember correctly it was an issue with the gasket material being delaminated from the exposure to the newer generation of Organic Acid Bassed coolants.
A search over there may turn up the thread, but I've heard that the archives were toated when they got new servers.
Tom