57 differential
Thread Starter
Instructor
Joined: May 2007
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From: Louisville Colorado
57 differential
Does someone have differential casting # for an early (Oct 56) 57 vette? Are the differentials (non-posi) for 57 vettes the same as Chev passenger cars?
Thanks
Thanks
Tech Contributor
Joined: May 2005
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From: Conroe Texas
Found this recent thread
http://forums.corvetteforum.com/show...differential+P
I thought I had seen another recently on differential differences, but I'm still looking for it...
http://forums.corvetteforum.com/show...differential+P
I thought I had seen another recently on differential differences, but I'm still looking for it...
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From: Mustang OK
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Gerry,
ALLLLLLLLLLLLLL 55-64 passenger car and ALLLLLLLLLLLLL 56-62 Corvette rearend center sections are a 100% bolt-in swap.
Furthermore, ALLLLLLLLLLLL of these rears, OF THE SAME YEAR, also share the same casting numbers and date codes. The differences between pass car and Vette rears (of the same year) will be the STAMPED code on the right side (passenger side) of the case.
For all practical purposes, there are three MAJOR differences in the center case:
1. 55-56 (no such thing as posi)
2. 57-64 NON-posi
3. 57-64 posi.
The 55-6 case was a thinner, lighter (translate weaker) case.
In 57, the cases were cast with longer, thicker, stronger webs where the bearing caps are attached with 2 bolts.
The 57-64 NON-posi cases have an additional gusset cast into the inside of the case which IS NOT in the posi cases. These are the MAJOR differences between 55-64 differential cases. There are several different casting numbers for the cases, but the cases of the above years basically share the same characteristics.
I need to add one note.
For Corvettes ONLY, the above style rear began in 56 (NOT 55). The rear changed for pass cars in 55.
The 55 Corvette rear is the same for 53-55 and shares LOTS of similarities with the 49-54 pass car rears.
ALLLLLLLLLLLLLL 55-64 passenger car and ALLLLLLLLLLLLL 56-62 Corvette rearend center sections are a 100% bolt-in swap.
Furthermore, ALLLLLLLLLLLL of these rears, OF THE SAME YEAR, also share the same casting numbers and date codes. The differences between pass car and Vette rears (of the same year) will be the STAMPED code on the right side (passenger side) of the case.
For all practical purposes, there are three MAJOR differences in the center case:
1. 55-56 (no such thing as posi)
2. 57-64 NON-posi
3. 57-64 posi.
The 55-6 case was a thinner, lighter (translate weaker) case.
In 57, the cases were cast with longer, thicker, stronger webs where the bearing caps are attached with 2 bolts.
The 57-64 NON-posi cases have an additional gusset cast into the inside of the case which IS NOT in the posi cases. These are the MAJOR differences between 55-64 differential cases. There are several different casting numbers for the cases, but the cases of the above years basically share the same characteristics.
I need to add one note.
For Corvettes ONLY, the above style rear began in 56 (NOT 55). The rear changed for pass cars in 55.
The 55 Corvette rear is the same for 53-55 and shares LOTS of similarities with the 49-54 pass car rears.
Last edited by DZAUTO; May 20, 2008 at 11:42 AM.
Thread Starter
Instructor
Joined: May 2007
Posts: 140
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From: Louisville Colorado
Thanks 62Jeff and DZAuto. I don't have the #'s at my finger tips but I think my '57 has a 61 or 62 posi. Would like to take it back to original and was wondering what differential would be correct. There was an Oct 56 diff for sale on Ebay but I believe it was from a 56 Belair so according to DZ, this would not be a correct housing for my 57.
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From: Mustang OK
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Thanks 62Jeff and DZAuto. I don't have the #'s at my finger tips but I think my '57 has a 61 or 62 posi. Would like to take it back to original and was wondering what differential would be correct. There was an Oct 56 diff for sale on Ebay but I believe it was from a 56 Belair so according to DZ, this would not be a correct housing for my 57.
PLUS, this brings up one more important issue. Even if the case has the correct casting number for a 57, it MUST be from the correct rearend assembly plant. The rearends for Corvettes ONLY came from one assembly plant, which is the Detroit Gear and Axle plant. The other rearend plant was Buffalo (NY). It is VERY EASY to determine if a rear came from the Detroit or Buffalo plant. The CAST date on the Buffalo rearends, ends with TWO numbers for the casting date, such as A2557 for Jan 25, 1957. The casting date on a Detroit rear will end with only ONE number for the year, such as A257 for Jan 25, 1957. Of course, if the rear you are interested in was cast in Oct 56, then the date code would need to be something like this, J196, for Oct 19, 1956.
Hope this helps.
Last edited by DZAUTO; May 22, 2008 at 07:22 AM.
