Help decoding 230ci engine stamp

[Praxiss454]

This is a bit of a cross-post from another thread, but no one had an answer and I thought moving the engine-specific question here might yield some more help. Hope this is okay.

I have a 65 GMC 1000 with what appears to be an original engine, but the stamp on the engine leaves me puzzled. The block casting number (3850817) says this is a 62-78 230-250. I assume the bottom half was painted at some point after the fact w/ that blue color, when the PO was doing some maintenance.


However, the engine stamp appears to be F0904Z01 and then a much fainter "238" (I think, can't quite make it out)
From various decoder websites I gather F - Flint, 0904 - Sept 4. What about the rest of it? Was hoping to be able to confirm that this was the original engine, OR identify what kind of vehicle this one came out of.


Thanks