Here it is:
12 bolt (counted) --->No cover.
#3917124N
RA 0429K (?what I could make out from the Pass tube)
GM2 D N (?what I could make out from lip on housing)

OK I did tons of searches and only came up with it is a 67-9 rear axle based off the #...but nothing else matches up...I tried different eyes, and of course it does not photograph well.

It is ~55 3/8" long...from flange to flange (which I assume is what the backing plates bolt to?)

I plan on swapping this into my '70 chevelle with 3.55 or 3.73 POsi, so want to make sure it will be fine. Any useful info available will be greatly appreciated.

THanks.

The casting number was used for late 67,68 and early 69. The axle width is
68+ and April is too early for 69 so I think it is a 68 rear.
0429=April 29th axle assembled date
K=McKinnon axle plant (Canada)
RA= In 68: Oldsmobile with Chevy C clip axle. non posi 2.73 ratio
41/15 teeth count
The Oshawa Canadian plant was using Chevy 12 bolts for the Cutlass w/455 starting in 68.

Thanks, shooter.
You were very thorough. Where did you get all your info from?

SO I assume that these rearends are interchangeable for a 1970 chevelle?

Thanks.

It will interchange because it is a Chevrolet rear. Just has an Olds
application stamp, only difference.
Here is a link to the Olds info. Check the differential usage paragraph about using the chevy axle in the Canadian 442. (Early 70's GTO with the big engine also got the chevy 12 bolt rears.) The ratio chart is at the middle of page.
Hope this helps.
http://www.442.com/oldsfaq/ofdif.htm#DIF%20Differential%20Codes

Thanks again, shooter.

It is the same length as a Chevelle SS 12 bolt then?

(sorry if I am asking a dumb question,
but I just cannot seem to find anything definitive)

Thanks.

Yes, 68-72 Chevelle is same length you measured. 64-67 is 1" shorter.

Thanks shooter.

If I can get your thoughts on, 3.55 or 3.73 gears....for all around driving.
(Running with a slightly beefed 396, T400, w/ 3500 stahl & good tires)
Will it be that much of a difference off the start?

Well, thanks for all your help with the decode, shooter.