Can you tell what model of car an engine came in just by the stamping on the side of the block? Ya see, I have this 340....

Some engine block must have been stored for some time. For instance, '78 was the last year they made 440's, but, you could get 1980 motorhomes with a 440. I don't know if the engines were all assembled in 1978 and then stored before they were dropping into a MH chassis, but, I would think the engine would have been built closer to when they were installed. From what I've seen in old photos, bare block castings were left outside to be "seasoned" before they were machined. I sounds pretty likely that they were not likely to be out there in exact numerical order. Getting one out of sequence would be easy to do.