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63 rear end info needed

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Old 10-01-2013, 05:38 PM
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lonzoo
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Default 63 rear end info needed

Where is the code on 63 vette that tells what ratio the gears are?
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Old 10-01-2013, 05:58 PM
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Michael H
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On the underside flange right where the back cover bolts to the rear housing there are codes.



for '63, here are the two letter codes

CA - 3:36 standard, manual or PG
CB - 3:36 Posi, manual or PG
CC - 3:55 Posi, 4spd
CD - 3:70 Posi, 4spd
CE - 4:11 Posi, 4spd
CF - 4:56 Posi, 4spd
CJ - 3:08 Posi, 4spd
CX - 3:70 Std, close ratio 4spd
CZ - 3:08 Std, Wide Ratio 4spd

if you have others codes, post them and we can figure out what it was originally.
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Old 10-01-2013, 06:01 PM
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Michael H
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Just another note - I have seen these with codes that look like they were put on pretty carelessly. Letters jumbled all over the place.
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Old 10-01-2013, 06:24 PM
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Originally Posted by Michael H View Post
Just another note - I have seen these with codes that look like they were put on pretty carelessly. Letters jumbled all over the place.
Agreed Michael. Maybe they were put on Friday's at quitting time.
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Old 10-01-2013, 06:55 PM
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lonzoo
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My code reads CJ112762. It sure does not seem like that it is a high ratio..i thought it should be a 3:70???
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Old 10-01-2013, 07:06 PM
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Originally Posted by lonzoo View Post
My code reads CJ112762. It sure does not seem like that it is a high ratio..i thought it should be a 3:70???
"CJ" on a '63 diff is a 3.08. The 3.08 wasn't standard with any engine or transmission, but was optional with any engine and a 4-speed transmission as an "economy" axle.
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Old 10-02-2013, 01:38 PM
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Originally Posted by Michael H View Post
On the underside flange right where the back cover bolts to the rear housing there are codes.



for '63, here are the two letter codes

CA - 3:36 standard, manual or PG
CB - 3:36 Posi, manual or PG
CC - 3:55 Posi, 4spd
CD - 3:70 Posi, 4spd
CE - 4:11 Posi, 4spd
CF - 4:56 Posi, 4spd
CJ - 3:08 Posi, 4spd
CX - 3:70 Std, close ratio 4spd
CZ - 3:08 Std, Wide Ratio 4spd

if you have others codes, post them and we can figure out what it was originally.

Don't these codes like "CA" - 3:36 indicate whether the manual transmission was a 3 speed or a 4 spd?

Syd
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Old 10-02-2013, 01:51 PM
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Michael H
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Info I posted was out of the NCRS Spec Guide, so all I can think of is that the CA and CB were all that was available for 3spd manual cars. I doubt that this is the case, maybe others can chime in and comment.
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Old 10-02-2013, 02:17 PM
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MrPbody
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Originally Posted by lonzoo View Post
My code reads CJ112762. It sure does not seem like that it is a high ratio..i thought it should be a 3:70???
63 and 64 had the weaker posi, so a lot of them don't have original rear ends any more. my 64 diff has a code for a 66 big block 3:55 ratio, but actually has a 4:11 ratio gearset in it. count teeth or rotate tire and count turns is the only way to be sure.

Russ
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Old 10-02-2013, 05:02 PM
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Originally Posted by Michael H View Post
Info I posted was out of the NCRS Spec Guide, so all I can think of is that the CA and CB were all that was available for 3spd manual cars. I doubt that this is the case, maybe others can chime in and comment.
That's correct - see post #6.
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Old 10-02-2013, 08:19 PM
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unless you know the rear and the rest of the vette are original, the gears may have been
changed over the years. jim
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Old 10-03-2013, 07:42 PM
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Did the rotation and it comes out to be 3:70. Must have had gears installed because it is a CJ (3:08) code.

thanks guys







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