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Old Jan 10, 2010 | 12:10 AM
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Default Date code question

In looking for an extra rearend for my 65, I came across one with a code F 21 9. How can you tell if it is a 1969, or 1979? Thanks Ron B.
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Old Jan 10, 2010 | 12:45 AM
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1978 and 1979 had small bolt holes for the spring. They were 5/8" for '63 to '77 and 1/2" for '78 and '79.


Or maybe it is 1/2" and 7/16". I can't remember.


No one judges the date codes on the rears anyway.

Last edited by Procrastination Racing; Jan 10, 2010 at 12:51 AM.
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Old Jan 10, 2010 | 04:16 AM
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The coding on the rear end on my car is somewhat strange. After what i can tell it is either CZ or CX on my 1964.
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Old Jan 10, 2010 | 11:09 PM
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CX code would be a 3:70 non-posi rear mated with a close-ratio 4 speed. The CZ code is 3:08 non-posi mated with Wide-Ratio 4 speed.
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Old Jan 11, 2010 | 03:25 PM
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It can also be OAW 290 F. That is the number i have written down in yhe book with all the papers with th numbers for my v\car. Wrote it down years ago.
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Old Jan 12, 2010 | 12:40 PM
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Originally Posted by TheSaint
It can also be OAW 290 F. That is the number i have written down in yhe book with all the papers with th numbers for my v\car. Wrote it down years ago.
That date code format wasn't used on diffferentials until 1971.
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Old Jan 12, 2010 | 01:40 PM
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I suppose i got to get under car to check it again but its to cold outside right now
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Old Jan 12, 2010 | 10:57 PM
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Since the rear end was not a real strong part of the drive train, many got replaced and many were replaced to get a more desirable gear ratio.

Don't be surprised if the numbers do not match. It is also hard to get under and to read them, so many owners never did, or didn't worry if they were wrong.
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Old Jan 13, 2010 | 03:36 AM
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I see. For sure like the ratio on my car
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