They're closing the iron foundry, the engine plants (there's two of them) are still going strong, at least one of those engine plants is where the Duratec motors are manufactured. The Duratec motors utilize 100% aluminum castings however. Since Ford's normal business model is to build the foundry next to the engine plant that will use the parts cast in the foundry, its a wonder the iron foundry was kept going as long as it did. Ford won't let the foundry sit idle, capital will be invested to prepare the foundry for its next mission.
If you're looking for a spiritual descendant of the 351C, the Duratec motors are it. Whereas the 351C design was heavily influenced by Ford's 1963 OHV Indy racing motor, the design of the Duratec motors was influenced by the 1964-1965 DOHC Indy racing motors. In other words, the R&D performed by the guys working for Bill Gay between 1963 & 1965 influenced both engines.
-G