Cast dating on differential covers

[Wayne M.]

Here's a pic of a ...375 casting number cover with a cast date near the fill plug of A_9_9 (Jan 9th 1969). I'd like to get your opinion on whether this cover might be original to the rest of the differential assembly, with a 3899143 cast # carrier (cast date I_11_8; ie. Sept 11th, 1968), and an assembly stamping of 2AL_10_22_68_W (22nd October 1968, 3.08 posi ratio small block).

I suppose I'm indirectly asking if the carrier and internal posi case and yokes were assembled and code-date stamped on the bottom of the carrier before the rear cover was bolted on.

And while I'm at it, when did the first reported casting cover dates begin ?

[Edward J.]

Re: Cast dating on differential covers

Wayne, I don't know if this helps but my 72 codes are , diff. cover is C222 and the main case is C142, the car is a April 19,72.

[Wayne M.]

Re: Cast dating on differential covers

Wayne, I don't know if this helps but my 72 codes are , diff. cover is C222 and the main case is C142, the car is a April 19,72.

Every response helps, Edward. Yours has an 8-day span between castings. Happen to know what your assembly stamping is ?

How about the other early C3 owners ? Terry M ? ... anyone ? Bueller ?

What do the early C3 TIM&JG's have to say about dated rear covers (as info only, not judged) ?

[Edward J.]

Re: Cast dating on differential covers

Every response helps, Edward. Yours has an 8-day span between castings. Happen to know what your assembly stamping is ?

How about the other early C3 owners ? Terry M ? ... anyone ? Bueller ?

What do the early C3 TIM&JG's have to say about dated rear covers (as info only, not judged) ?

Wayne, the stamp looks like AW W104E does that look right? whats that date APR. 1?

[John C.]

Re: Cast dating on differential covers

Wayne

My 68 has a rear cover casting date of March 7th (c 7 8).

I only took a quick look but didn't see a casting date on the main case. Where is it typically located?

The final assembly date is March 27th (3 27 8).

It is the original rear end to the car.

John

[Wayne M.]

Re: Cast dating on differential covers

...My 68 has a rear cover casting date of March 7th (C 7 8).
I only took a quick look but didn't see a casting date on the main case. Where is it typically located?
The final assembly date is March 27th (3 27 8).
It is the original rear end to the car. ..

John, thanks for your data. The carrier casting number is located on the driver side, above the strut rod(s) bracket [you can see the indentation for it]. Pic shows my diff under discussion. Sometimes this feature is well preserved, especially if the output yoke leaks . Interesting to see the difference between the letter "I" (September) and the "1"s in the number eleven.

[John C.]

Re: Cast dating on differential covers

John, thanks for your data. The carrier casting number is located on the driver side, above the strut rod(s) bracket [you can see the indentation for it]. Pic shows my diff under discussion. Sometimes this feature is well preserved, especially if the output yoke leaks . Interesting to see the difference between the letter "I" (September) and the "1"s in the number eleven.

Wayne

I found the main case casting date. It is Dec 27th 1967 (L 27 7).

John