"Peening" on late production 69 axle codes

[cook_dw]

No reason to pull all the verbiage from the other thread.  No comments about respect or opinions.  What I would like to see if there are others out there in the Aug - Oct timeframe that have the "peened" area over the "C".

[cook_dw]

More info.


Info as I have it currently.  Please feel free to add your info.  Thank you.

[69Z28-RS]

Well..  when the other thread was closed/slammed/whatever happened to it, I lost the data I posted relative to the optional Nova rear gear ratios for 1970 (The '70 Nova rear for multiple leafs would have been identical to the *late* '69 Camaro rears where the ratios existed on both cars!  (Looked it up again)...

The 'BS' ratio (3.31:1) WAS available on the '70 Nova, so the rear end noted without the 'C' peened would most likely have come from a Nova.  The 'BU' and 'BE' ratios were not available on the '70 Nova, thus the leading 'C' for the 1970 year would not have been indicated for those ratios, but late '69 Camaros with BU or BE ratios *might* have been stamped with the leading 'C' (for 1970 models) in the axle plant before someone noted they were going into '69 model cars (Camaros)... (and obliterated the C)...

[BULLITT65]

I am hoping Bentley has some contributions. I think he mentioned in the other thread that he had seen a BE with a peened C. I also am going to inquire with a nova site I am on and see if I can possibly get some examples from them.

[69Z28-RS]

Based on our hypothesis (that 'late' Camaros that used rears that other '70 model cars) got the C's peened/obliterated...  Nova rears would NOT have the peened characters (if the rears are original to Novas) since Novas did not have extended production from '69 leading to the '70 model year.   Only Corvettes and Camaros (suffered or benefited?) from the extended production and corvettes used a totally different rear end type (IRS)...

That said... since Novas and Camaros share the same rear end width, there have been a LOT of swapping of rears between the two car models over the last 40+ years!

[cook_dw]

I understand the basis of the scenarios and hypothesis but for me personally do not want to post any of that at this point.  I would rather let the data speak.  I also realize that the spreadsheet above is "down and dirty" and will need to be expanded on in the future but I just wanted to get something down.


1970 Nova differential codes

CBA - 2.56 open 10-bolt
CBB - 2.56 posi 10-bolt
CBC - 3.36 open 10-bolt
CBD - 3.36 posi 10-bolt
CBL - 3.07 open 12-bolt
CBM - 3.31 open 12-bolt
CBN - 3.55 open
CBP - 2.73 open 10-bolt
CBR - 3.07 posi 12-bolt
CBS - 3.31 posi 12-bolt
CBT - 3.55 posi
CBW - 4.10 posi 12-bolt
CPA - 3.08 open 10-bolt
CPE - 3.08 posi 10-bolt
CPI - 2.56 open 10-bolt
CPJ - 2.56 posi 10-bolt
CPO - 3.08 open 10-bolt
CPR - 3.08 posi 10-bolt
CPX - 2.73 posi 10-bolt

[KurtS]

Edited, a lot.
Simple rules to this post - post facts and data. Postulate after data is accumulated.

[KurtS]

Going through my pictures and only listing the axles were the C was visible and clear. If it wasn't a good pic, I didn't make a call.
Interesting that there are dates like CBU0829 that are both peened and not peened. 1 BE was peened, several weren't.
FWIW, late 69 BB engines also had the C added to the application code.

not peened
CBA0804
CBS0805
CBL0806
CBS0820
CBL0812
CBU0819
CBQ0821
CBA0827
CBU0828
CBU0828
CBU0829
CBS0829
CBT0902
CBU0915
CBU0918
CBU0918
CBT0922
CBT0924
CBS0926
CBM0928
CPI1003
CBU1007
CBU1008
CBU1009
CBT1013
CBR1015
CBT1021
CBM1022
CBM1028

peened
CBU0818
CBU0818
CBU0827
CBU0829
CBU0829
CBU0910
CBU0922
CBU0929
CBU1003
CBU1006
CBU1017
CBU1022
CBU1017

[cook_dw]

Peened BE  0922G2

Original diff under a 20K mile original COPO.  Grease was removed for the first time this past July.

[bcmiller]

Note here from the Chevrolet Dealer Service Information Bulletin dated September 29, 1969.

The first C in the code designates it as a Passenger (car) type axle versus Truck. This is for very late 1969 model year axles and continued into 1970.  Things changed again in 1971. Remember that GM "Corporate" 10 bolt axles were gradually implemented in the early 1970s.

[bcmiller]

Thought the information above might be of interest to some.

[69Z28-RS]

Bryon,

Is there some 'new' information on that documentation, that isn't obvious? 

[cook_dw]

Thanks for posting.

[bcmiller]

Bryon,

Is there some 'new' information on that documentation, that isn't obvious? 

GM documentation which shows why the C is supposed to be there.

Production code numbers will contain prefix letters, production date numbers and a suffix letter.

[69Z28-RS]

I didn't know there was any question about that for 1970 model year Chevrolets....