Ok so I recently bought a 1965 Corvette. The last 3 numbers on the deck have been stamped over to match the vin Does anybody know if GM ever did this because I ran the other numberunder the restamp and it is 1 day prior of production date of my vin. ????? Or do you think someone found a correct date coded block that was close to the vin # Im baffled

 

There was a such thing as factory grind outs where they did such things. How you tell them apart from someone who did it 50 years later I have no clue

 

Please post a pic. That will really help.

 

i ran the vin under the car vin and it says that car was produced 1 day before my car???????????

 

The factory did do odd things . . here is a pic of my original rear frame stamp from the factory. The front vin stamp was correct and not like this "mistake".

 

Its kinda believable, actually.

 

Well, three possibilities 1) it’s factory re-stamp on an engine that was pulled the previous day for a repair, or other odd reason. Not likely, as the factory would not have even tried to align things so perfectly. 2) It’s a factory stamp (for the earlier car) where someone re-stamped the VIN back in the day (before anyone cared about originality) and put it your car. Or 3) it’s the dumbest, most bubba’d restamp ever.

 

How about... the line worker picked up the wrong gang stamp, one from yesterday, stamped it, went "Oh, ****" when they realized what happened, then fixed it.

 

why would he have one laying around with 200 cars before that one’s vin and it hadn’t been changed.

 

I have to ask, did you know this before you bought the car?

 

The "twos" do not look the same . . the curve on the second "2" doesn't match that of the first so . . my guess is restamp by a non factory person.

 

Only the last 3 digit positions were stamped twice. How would that have been accomplished with a gang stamp? The alignment looks pretty good except for the 4.

 

Because that was the last car it stamped, then they went to a new one. Laid it aside when it probably should have been put it away somewhere. At some point it accidentally got picked up?

That's my guess... and it seems more plausible than someone just happening to find an engine from the previous day and doing the worlds worst restamp in an attempt to counterfeit matching numbers

 

would be interesting to know how the off line heavy repair section of the line handled engine stamping if a problem occurred.

 

It doesn't seem likely that someone offline doing repairs would know what vin the engine would need stamped on the pad.

 

it would be if at the end of the line they had a failure

 

I believe Al Grenning is the foremost expert on Corvette stamp pads in the world. Al has spent the last 40+ years studying and photographing engine stamps, and has interviewed the people at Tonawanda, Flint and St Louis responsible for stamping the pads. Al regularly does seminars for the NCRS on stamp pads and I've been to a number of them. From what I've learned, typically when a mistake was made when stamping a pad at either the engine plant or the assembly line they did a grind out. A grind out is just what it sounds like, they took a hand held grinder, ground off the mistake and restamped the pad with the correct information. From photos I've seen it's pretty obvious when a grind out has been done because the grind out leaves an obvious circular grinding mark under the stamping.

I've never seen a pad that had a new number stamped over another one, except in the case of a double tap, and I'm not sure it's even possible for it to happen with a different number on the assembly line. How the gang holder was used as described by Al Grenning, was that at the beginning of each shift the gang holder was loaded with the first VIN to be stamped. Once that first block was stamped, only the digit(s) that needed to be changed for the next VIN were removed from the holder and replaced. If the first VIN stamped was xxxxxxx410003, only the "3" was removed and replaced with the "4". This would continued till they got to 10009, at which point both the "0" and the "9" would be removed and the "1" and "0" were added. This would continue till the end of the shift, when the gang holder was emptied completely. It was probably done this way because the person doing the stamping probably didn't have the time to empty and fully reload the gang holder for each VIN, and there was no need to completely empty it for just one or two digits. If this is the way that they stamped VIN's at St Louis, and I believe it is, there's no way that a block would be stamped with three wrong digits unless they were going from "099" to "100", "199" to "200" etc., which is not the case here. Occasionally something would happen like dropping the gang holder and the stamps would fall out and need to be reloaded, but even in this case if a mistake was made it would likely be made by putting the right digits in the holder, in the wrong order. From the numbers I see on that pad that couldn't be the case with this VIN.

I'm not willing to say that it's 100% not a factory screw up, if for no other reason then the broach marks are there and look good, but what I see is completely outside what I've learned would be how a mistake was usually corrected.

This is a pad that really would be worth having Al Grenning at CCAS Affirmation review, but the cost to do this is not cheap. I think he's now charging around $1500 for his expertise.

https://www.ccas4vettes.com/

 

Factory grind outs and restamps are very well documented...overstamps not so much.

 

Do both VIN’s still exist today?

DAN

 

As an update I was informed by Al that his fees vary based on things like the year of the car and the particular engine. He told me this pad would be $750 to review, not $1500.