I just checked the place I bought mine and they don't list them anymore. Also checked Blueovalindustries. The price went up to what you are finding them for now. Looks like the supply evened out.
I bought mine in July 2006 when all the Ford FRPP dealers were starting to remove the heads from crate engines and sold them as "take off" heads that were never fired. $724 to my door. They were installing the new 'Z' heads on these engines.