[Barnsnake]

They should be aware that Ford almost never stamped a vehicle number on an engine (in the U.S. anyway). Casting numbers are all you have.
The C6ME is an FE block casting from a 1966 model or later. (Used in many configurations. Bore and stroke likely needed for full I.D.)
5K19 is 9/19/1965 (would mean 1966 model production)

Any more will need to come from one of the FE gurus.