Diff housing stamping code

[69427]

Got a spare rear housing sitting around. I'm just curious what all the stamp code means. I gotta couple guesses, but there's still a couple unknowns.
Thanks,
Mike

1AM4 22 68W

 

[Twin_Turbo]

I'm guessing:

AM = Posi 3.36:1
4 22 = April 22??
W = Warren

 

[SmokinBBC]

I'm guessing:

AM = Posi 3.36:1
4 22 = April 22??
W = Warren

Good Guess. I came up with the same thing. Date is April 22 '68. The 1 in front indicates it was built during the first shift.

 

[BBShark]

68 is a different casting number than 69-up (number is near the pinion yoke on the passenger side), I think. Gary would know

APB for GTR1999:trumpet:

 

[GTR1999]

yeah that looks like a 68 diff. Check the casting date where BB mentioned - should be a few month before the stamped date.
The 63-68's are ok but not what I would use for a 12 bolt. They are narrower inside between the bearing pads. Look at the posi case, if it has a small sq window it's the original- unless it's an open diff. Another clue is the bearing caps. Id they don't have a cast in tab on the outside edge they're the 68's.
They will also use the thin shims, usually between 070-090"

 

[69427]

Thanks for the info, guys. Not that it matters, but it just occured to me that this rear end used to be in a race car that got included in the picture section of the Corvette book, Star Spangled Something or other. I got a bunch of parts from the guy after he stopped running the widebody C3 and ran a C4 in Trans-Am for a couple years. (The T/A series was a helluva money pit, near as I could figure.)

 

[Twin_Turbo]

Race car parts? Details please

 

[69427]

Race car parts? Details please

Sorry to say, not many details to tell anymore. I kept most of the parts I could use on my '69 (an assortment of drivetrain parts, bearings, seals, and a couple of other odds and ends), but parted with a bunch of the other stuff when I moved from up north down to Florida a couple years ago. I had a pole barn (and lots of room) on my property up north, but I had to downsize my spare parts supply to fit in my present attached garage. It's been an adjustment.