DZ Block & Assembly Date
 

Just curious about the same day casting & assembly date on this DZ block.

Not sure I can help with that one Jeff but an interesting stamp. Personally, I have not seen that date before and although IMO it looks like a legit stamp with very prominent broach marks, it really does appear quite clean and almost a bit clinical looking.

If I recall, the casting foundry was offsite and separate from the Flint engine plant, so I would imagine it would be highly unlikely for a block to be cast, cooled, delivered and then machined/stamped in another facility on the same date. One would think that Flint would have to be completely out of blocks all together, and then send for fresh foundry cores on the said casting date in order for the machine shop to build and stamp the block on the same date. I would also think the core would still be green, and highly unlikely as suitable for machining on the same day would it not? Core shift comes to mind here.

It will be interesting to see what others have to say on this one. :scholar:

I have a relatively small db with two examples of same-day casting/assembly. One or two day differences are not unusual.

The stamp matches other September '69 examples. I see no reason to question it.

This has been noted by John Z and others before. NCRS has documented examples of this. Flint blocks were cast in Saginaw Michigan, then trucked continuously by dedicated semis to Flint Michigan and it was possible for a block to be cast early in the 1st shift at Saginaw and then show up at the Flint Engine plant on 2nd shift for machining and assembly.
It happened more in the Tonawanda plant as casting/machining/assembly were in same building/plant.

From CRG Drivetrain decoding http://www.camaros.org/drivetrain.shtml:

When the examples of same day casting and assembly we were skeptical but a few have surfaced. Kind of amazing that this actually occurred.

Good stuff to know. I remember reading some of John Z's threads over the years on TC and CRG but couldn't recall if same day dates were accepted. Also didn't know that Sag could hump the blocks down to Flint on the same day.

Still curious...were the blocks still green at this point and was core shift a concern?

Thanks for all the responses & answering all my concerns as well. This block has been in storage for over 20 years & has just been freshly cleaned & bored .040.

Look at the casting clocks on the block - same day engines would typically be cast at the beginning of a shift.