1957 corvette
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1957 corvette
on a 57 vette 270 horse dual quad should the engine pad have part of the vin number. also is it possible to have an engine made jan 8 and the car in july.do 57 pos rears have a P on the case thanks
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From: Beverly Hills/Pine Ridge Florida
57's should not have part of the VIN on the pad, just the assembly date and suffix.
That's a LONG time between casting date and car assembly.
To the best of my knowledge, all posi cases have a large, elongated "P" on them.
Chuck
That's a LONG time between casting date and car assembly.
To the best of my knowledge, all posi cases have a large, elongated "P" on them.
Chuck
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From: Emporia, pay no attention to that man behind the curtain, KS
I don't have my black book in front of me, but I think I can answer your questions off the top of my head.
The VIN did not appear on the engine pad until mid to late '60.
I believe it is acceptable to NCRS judging for the engine to have been manufactured up to around six months before the car was assembled. So, dates should be acceptable. If I am wrong, someone who knows NCRS judging better than me will chime in.
I believe all factory posi cases has the cast "P".
The VIN did not appear on the engine pad until mid to late '60.
I believe it is acceptable to NCRS judging for the engine to have been manufactured up to around six months before the car was assembled. So, dates should be acceptable. If I am wrong, someone who knows NCRS judging better than me will chime in.
I believe all factory posi cases has the cast "P".
Live Free or Die
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From: One thing is for sure this kind of discourse and BS would not be tolerated on the NCRS forum. Ohio
The early posi rears had no P. I'm sure someone will correct me if I'm wrong, but IIRC I don't think the "P" appeared until March or April.
On the early housings I believe they had no external markings and then some had an "X" on them. The "X" housings usually sell for stupid money.
On the early housings I believe they had no external markings and then some had an "X" on them. The "X" housings usually sell for stupid money.
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Posi was first available about Dec 56.
The first posi cases DID NOT, repeat, DID NOT have any indication of posi, except the casting number and the stamped code (plain case).
Then, about the end of Jan/beginning Feb 57, the posi cases had an X cast near the big GM.
About Apr 57, the X was replaced with the big P.
Rears were built at the Buffalo (NY) plant and the Detroit Gear and Axle plant.
Corvettes got rears ONLY from the Detroit plant.
The stamped code on Buffalo built rears will begin with a B.
The stamped code on Detroit built rears will begin with an A (later HD brake rears will begin with an F).
Buffalo posi rears will have a thick P.
Detroit posi rears will have a thin P.
Thus, CORRECT Corvette posi rears will have a thin P (the ones built after Apr 57) and a stamped code beginning with an A.
Buffalo posi (thick P).
Detroit posi (thin P)
The first posi cases DID NOT, repeat, DID NOT have any indication of posi, except the casting number and the stamped code (plain case).
Then, about the end of Jan/beginning Feb 57, the posi cases had an X cast near the big GM.
About Apr 57, the X was replaced with the big P.
Rears were built at the Buffalo (NY) plant and the Detroit Gear and Axle plant.
Corvettes got rears ONLY from the Detroit plant.
The stamped code on Buffalo built rears will begin with a B.
The stamped code on Detroit built rears will begin with an A (later HD brake rears will begin with an F).
Buffalo posi rears will have a thick P.
Detroit posi rears will have a thin P.
Thus, CORRECT Corvette posi rears will have a thin P (the ones built after Apr 57) and a stamped code beginning with an A.
Buffalo posi (thick P).
Detroit posi (thin P)
Last edited by DZAUTO; Mar 20, 2008 at 07:24 PM.
Safety Car
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From: Bandera Texas
No vin number until 1960. I have vin # 1617 with a vin number stamped.
Positration answer is from Tom and right on the money.
I currently have a real #3743833 case (used in 1957 only) with a very small "X" positioned on the right side of the casting number. It is a postrication unit dated 'A187 ' (Jan 18, 1957) and I will sell it.
Every factory engine that I have seen installed as well as records that Mike Hunt discovered from original cars in the 70's, has an engine date about two to three weeks prior to the built date of the car. The actual build dates of 57 Corvettes has never been completely released as Chevrolet never could find the data. The Black Book and NCRS Judging manual has very good estimates, but also some conflicts.
In any case, the 6 month window NCRS has used for years is very generous at best. 3 to 5 weeks is much more realistic.
Positration answer is from Tom and right on the money.
I currently have a real #3743833 case (used in 1957 only) with a very small "X" positioned on the right side of the casting number. It is a postrication unit dated 'A187 ' (Jan 18, 1957) and I will sell it.
Every factory engine that I have seen installed as well as records that Mike Hunt discovered from original cars in the 70's, has an engine date about two to three weeks prior to the built date of the car. The actual build dates of 57 Corvettes has never been completely released as Chevrolet never could find the data. The Black Book and NCRS Judging manual has very good estimates, but also some conflicts.
In any case, the 6 month window NCRS has used for years is very generous at best. 3 to 5 weeks is much more realistic.
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374833 posi rear end for sale; D17 date code
I have a posi rear end casting #374833 with date code D17. It has a small P and about 4.25 gearing based on spinning it and counting rotations. I have not opened it up. Any interested in buying it?
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If it still has factory gears, and it is a 4-series posi, it will be either a 4.11 or 4.56. There was no other 4-series ratio between.
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Pic of 270 hp 1957 Corvette stamp pad
No VIN. Stamp could also have more numbers based on double digit month. Example- FII27EG. Positioned in the bottom left corner of the pad.
Garry
Safety Car
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From: Bandera Texas
The early posi rears had no P. I'm sure someone will correct me if I'm wrong, but IIRC I don't think the "P" appeared until March or April.
On the early housings I believe they had no external markings and then some had an "X" on them. The "X" housings usually sell for stupid money.
On the early housings I believe they had no external markings and then some had an "X" on them. The "X" housings usually sell for stupid money.
Racer
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From: Langley British Columbia
1957 Posi Rears
[QUOTE=DZAUTO;1564639968]Posi was first available about Dec 56.
About Apr 57, the X was replaced with the big P.
Rears were built at the Buffalo (NY) plant and the Detroit Gear and Axle plant.
Corvettes got rears ONLY from the Detroit plant.
The stamped code on Buffalo built rears will begin with a B.
The stamped code on Detroit built rears will begin with an A (later HD brake rears will begin with an F).
Question:
Where is the stamped code located? Does it show up on the 'X' rears?
Al
About Apr 57, the X was replaced with the big P.
Rears were built at the Buffalo (NY) plant and the Detroit Gear and Axle plant.
Corvettes got rears ONLY from the Detroit plant.
The stamped code on Buffalo built rears will begin with a B.
The stamped code on Detroit built rears will begin with an A (later HD brake rears will begin with an F).
Question:
Where is the stamped code located? Does it show up on the 'X' rears?
Al
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From: Washington Michigan
Racer
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From: Langley British Columbia
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The stamped code on SOME rears is very hard, sometimes nearly impossible, to read. I guess it depends on how big of a hammer was used to hit the stamp, or, how hung over the assembly worker was that day. In any event, some codes are deeply stamped, some are not. With years of accumulation of dirt, grease, crud, etc, you may need to use a fine wire brush and plenty of solvent to get the area clean enough to read the code.
The code should begin with the letter A followed by a second letter and then followed by 3-4 numbers.
The code should begin with the letter A followed by a second letter and then followed by 3-4 numbers.
