Nearing the due date of Chrysler ending production of any vehicles with 440's, advance orders from commercial 440 customers poured in. Chrysler fulfilled back orders for the 440 well past the vehicle production end date, all with 1978 date codes.
Winnebago, the best customer because of the huge amount of Dodge chassis/engine units they bought received these units until 1980, I think, with 1978 engines showing a 1978 casting date. That tells me blocks with 78 markings were cast for two more years.