Once again, I think there is some misunderstanding. The OP back in 2007 was looking for mechanical gauges. I believe that subsequent postings were looking for electronic AC Delco gauges which have not been produced for many years and are almost impossible to find.
As Ralph stated, mechanicals can be found from several manufacturers, but the OEM electric senders and gauges are not available but could be replaced as long as the sender and gauge are replaced together (and they will not look the same as those old AC gauges).
And related, but kind of off topic, why do people quote posts that are years old instead of starting a new thread?