Differential casting Clock

[Gary R.]

I am building a 67 diff for my friend Gary and see there is no "clock" on the lower right side. I don't recall ever seeing it missing from the 100's of diff's I built. Has anyone seen this before? Just curious.

[Hebert K.]

20251101_171520.jpg Gary,
My 67 differential does not have a clock.
It is rougher in that area, than the one in your photo but it doesn't look like a clock was there.
Date is FB 11 22 66

Herb

20251101_172107.jpg

[Gary R.]

Thank you Herb for posting your picture. Interesting yours is also a '66 and I agree with you, it doesn't look like it was there. I have to go back in my files and check the earlier years now.

Add- I just pulled a 65 file and it has the clock?

[Mark F.]

Hi Gary,

Pointers and center screws attaching them seem more likely to be missing or cockeyed on any casting. But it puzzles me that the “D”, “N” and “Clock Nubs” shown in the image below would be missing.

The patterns for those castings would most probably have had the “D”, “N” and “Clock Nubs” permanently pressed (embossed) into the casting sand inside the mold. Yes, arrows (pointers) and screwed-on date codes (things that had to have line operator action each hour and/or shift and date) did fall off, or point to the wrong thing if they were not secured properly.

I don’t have access to my diff now or I would have tried to provide a picture.

The text and image below are from John Hinckley’s Oct '05 Corvette Enthusiast article: “Know the Code -Decoding all those Casting Symbols for your Corvette”

image.png

[Hebert K.]

Gary, Here is another 67 diff that I have that has the clock.
Date C 5 6


4.11 rear 2.jpg

[Gary R.]

I finished building this diff today. Here is another look at the clock area

[Hebert K.]

Here is the clock for post 5
4.11 rear 3.jpg