[Lanny Dale]

I have a recently bought 69 Malibu driver with a TH 400 and a 12 bolt RE. I assume this isn't original because its a Malibu with a 350. In trying to identify the RE, I found the number on the rh side axle tube that starts with the letters CN. Both my reference books tell me this is a '65, '66 or '67 - 3.31:1 non posi, which irked me right away because I already knew that the 68 and 69 RE's are about 1 inch wider. I also have a bare 12 bolt housing that is identified by KK which is listed as a 4.10:1 posi for a 68 or 69. My confusion is that both RE's are the same width at 54.5" flange to flange. To add to this I also have a 12 bolt posi which is in a project 67 SS convertible with 396 4 spd. I cannot read the number on that one because its quite rough with surface rust. I measured that RE and it is 53.5" flange to flange which tells me I'm measuring correctly. How can this "CN" identifier measure out to 54.5"? Did US and Canadian made RE's use the same codes? My 69 Malibu is originally from the US.

 

[DUTCH MAX HEADWORK]

What are the remainder of the numbers next to the CN.

It's possible that is the original rear end, barring the measurement issues as I'm weak on those. The 12 bolt rearend was standard with some 350's and could be ordered for others. It's not an SS or big block specific part.

1969 CN 2.56:1 ~ 12-bolt (L48/350-4 & LM1/350-4)*

1969 Chevelle Rear Axle Codes

Decoding Chevrolet VIN, trim tags, cowl tags, engine, engine block casting numbers, cylinder head casting numbers, intake manifold casting numbers, transmission, interior codes, and paint codes.

chevellestuff.net

It would be nice to have the casting number and casting date as you see in the following pictures, to help confirm.

 

[cheveslakr]

CN in '69 is a 2.56 non-posi 12 bolt code. I had this in my '69 350L48/Turbo 350. Fairly common.

 

[Lanny Dale]

What are the remainder of the numbers next to the CN.

It's possible that is the original rear end, barring the measurement issues as I'm weak on those. The 12 bolt rearend was standard with some 350's and could be ordered for others. It's not an SS or big block specific part.

1969 CN 2.56:1 ~ 12-bolt (L48/350-4 & LM1/350-4)*

1969 Chevelle Rear Axle Codes

Decoding Chevrolet VIN, trim tags, cowl tags, engine, engine block casting numbers, cylinder head casting numbers, intake manifold casting numbers, transmission, interior codes, and paint codes.

chevellestuff.net

It would be nice to have the casting number and casting date as you see in the following pictures, to help confirm.

View attachment 701110 View attachment 701111

CN 0311B, B 28 9 (date?) and 3959038 NF are the numbers. Based on your 1st reply, I see where I went wrong on my search. My reference material was (1) "Restoring Your Chevelle SS" and I don't think it references any parts that are not SS components. In any case it didn't show the "CN" identifier going any further than 1967. And (2) the other reference was "Chiltons guide to repairing Chevelles" and I didn't look close enough. The very last code for 69 RE's was "CN" which was indeed a 2.56:1 non posi. I also checked on the website you referenced to confirm that "CN" stopped in 1967 by looking at 1968 but not 1969 where it clearly identifies "CN" being a 1969 2.56:1 non posi. My bad! Thanks for the help.

CN in '69 is a 2.56 non-posi 12 bolt code. I had this in my '69 350L48/Turbo 350. Fairly common.

CN in '69 is a 2.56 non-posi 12 bolt code. I had this in my '69 350L48/Turbo 350. Fairly common.

Thank you as well cheveslakr, It all makes sense now after your and Dutch's replys. Just my inability to complete a search, lol.