68 Engine Block Missing Casting Date?

[69RALLYSPORTZ28]

Has anyone ever seen an engine block or heard of an foundry explanation as to why a 68 or early 69 engine block ( 327/302/350) would be missing the the casting date, unless the casting date was intentionally ground away during a rebuild?

[ko-lek-tor]

You are looking on the lower rh side of the center of water jacket? Correct? Probably will need a pic to clarify and see what you are seeing.

[69Z28-RS]

IIRC the foundry used 'letters' for 'foundry test' casting (to test new castings).  In some cases, those castings have been used.  I have seen one with an 'M' in the place of the casting date.

You should be able to find a thread addressing this issue which was discussed in the past.