The production date is Jan. 5, 1968. Don't know the HM code.
INSIST ON A PRESSURE TEST AND TRY TO BE THERE TO WITNESS IT.
Regardless of the skill of the repair I would not use this at more than 400HP. Hits down near the pan rail mean the big chunks broke. Coupled with the possibility of porosity, that's a vulnerable area. Breaks to the water jackets or
oil galleys are difficult to find. It may be fine for a 'correctness' motor but that's it.
It is surely not a good value or raw material to do a performance build. A better value and 'near correct' is a new Genesis iron block.