[rotorwrench]

Ford farmed out almost all replacement casting stuff after normal production of parts ended. Model A & B blocks were used in industrial & agricultural related applications long after the automobiles that used them had stopped production. I've only seen foundry marks on replacement transmission cases but not on engine block castings other then the diamond. Those that I have seen had the distinctive marking of Fairmount Tool and Forging Division of Houdaille Industries of Cleveland, OH but there were likely others too. Ford Motor Company seldom ever counted on any one supplier.