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Discussion Starter · #1 ·
Hey, First post.

I have a P2.93 stamped on the back side of the passenger side rear axle and assume that is the ratio and trying to figure out how that may relate to the differential. On the differential there's the number 92 written by hand in a yellow marker that seems to me like a marker used from a salvage yard. Stamped on the differential is a number 9773369 and from what I understand is the correct number for the 1964 pontiac tempest. In addition to that number I have a letter A stamped on the collar of the differential above the intersection of the axial and the differential. Also a faint stamp that looks like a CFD followed by a heavily raised number 2 located on the drivers side of the bottom of the differential. My confusion is what I believe to be the stamp which has what looks like a slotted screw on either side of this number: 149. From what I understand the "1" may be the capital letter "I" but I am not sure. If so, I understand the "I" may represent November and the following numbers the day and year. But that would make it November 4, 1969 and not the original differential . The differential cover is the standard 10 bolt pontiac pattern matching others of that year. Any thoughts on my confusion related the to possible I49 stamp and ratio?
Thanks
 

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Hi 64pont,

Welcome!

While I’m not as familiar with the 64’s as the other years, doing a brief search I found a fairly lengthy exchange on the same topic.

There are many qualified and helpful people here so I’m sure you will get lots of assistance.

Good luck and please keep us posted on what you learn.
 

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Discussion Starter · #3 ·
Hi 64pont,

Welcome!

While I’m not as familiar with the 64’s as the other years, doing a brief search I found a fairly lengthy exchange on the same topic.

There are many qualified and helpful people here so I’m sure you will get lots of assistance.

Good luck and please keep us posted on what you learn.

Thanks and will keep you posted.
 

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Discussion Starter · #5 ·
didnt 64's have the tiny upper control arm bushing ear on the case
pretty easy to tell em from a 65 up

Here are some photos of what I was mentioning above.
After cleaning it up I was able to see all the numbers stamped at the various locations. The photo showing the axil has the letter A on the top of the sleeve where the diff connects to the axil and also has the P2.93 to the right in the picture on the axil.
Notice the orange that appeared after the cleaning which I believe has significance. I believe the color may relates to a 3.08 ratio so am confused about the p2.93 marking on the axil and how it relates to the differential.

Thanks

IMG_0016.jpg IMG_0003.jpg IMG_2349.jpg IMG_0035.jpg IMG_0022.jpg Screen Shot 2021-02-02 at 9.55.27 PM.png
 

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I am going to say that the CFD seems to be associated with a "corporate" rear end, and the Pontiac rear was used in other A-body cars at that time. The "2" is most likely the indicator for "Pontiac" meaning the corporate rear end was destined for a Pontiac chassis.

I have not found any reference to the cast "A". It may indicate the A-body platform/chassis as this same A is used in later Pontiac 8.2 rear ends.

The grease pencil/paint may be the inspectors number, or assembler, who did the final assemble or inspect.
 

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dammm your car is clean under there !!

so looking at the pictures closer its a 64 model year differential
the upper control arm bushing boss is deffinatly a 64 model I can see it in picture 3 of the "92"
assembly mark ...flat casting in the front edge not round like 65-72's
also your P 289 3 in the last picture with the "A" is a julian date 289 (looks to me) 289th day of 63
middle of October ,,, when was you car built ?? november 63 ?
 

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dammm your car is clean under there !!

so looking at the pictures closer its a 64 model year differential
the upper control arm bushing boss is deffinatly a 64 model I can see it in picture 3 of the "92"
assembly mark ...flat casting in the front edge not round like 65-72's
also your P 289 3 in the last picture with the "A" is a julian date 289 (looks to me) 289th day of 63
middle of October ,,, when was you car built ?? november 63 ?
If you are referencing the "P2.93" it is the way they stamped the rear gear ratio on the '64's from what I found on the internet, so it is supposed to be a 2.93 rear gear. The Julian date on that rear is the "149".

The gear ratio list provided does not include all optional gear ratios. The AMA specs for the Tempest include gear ratios 2.56 & 2.93 for automatic cars, and 3.08 & 3.23 on the manual 326CI 2 bbl cars. The HO 4 bbl 326CI used 3.36 for manual, and 3.23 for automatics.
 
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