I must have missed something, 78 was the last year for the 440 's in the trucks, but the "B" series van and motorhome chassis and "M" chassis did recieve the 440 engine through the end of 79. There are some high end motor homes that are say 1981-1982 vintage that used what was left over of the "M" series chassis that had the 440's in them.
my 2 cents