DZ stamp opinion

[jeff400w]

Has anyone seen a DZ stamp like this?  I know it looks like a bad restamp, but I have owned this block since
1975. I knew the 2 previous owners of the car. To the best of my knowledge the motor had never been apart before
my friend,the previous owner spun a bearing and pulled it in 1973. It sat for a couple years before I got the short  block. You can see I had the blocked decked but made sure the stamping pad wasn’t touched.
Having an explanation on this makes a big difference on the value of this block.

[william]

It does not match up with other early September 1968 stamps.

[KurtS]

I looked at your pad before (fb?). I don't believe it's an original stamp.

[Delco115]

Just throwing this out there..... Is it possible the "Z" character could have been loaded upside down in the gang stamp holder, allowing it to be misaligned with the rest of the stamping?

I haven't seen an empty gang stamp holder in some time and am not real familiar with how the individual number/letter stamps are secured in it. Does anyone have detailed pictures of one and how it was loaded prior to its use?

[bcmiller]

Has anyone seen a DZ stamp like this?  I know it looks like a bad restamp, but I have owned this block since
1975. I knew the 2 previous owners of the car. To the best of my knowledge the motor had never been apart before
my friend,the previous owner spun a bearing and pulled it in 1973. It sat for a couple years before I got the short  block. You can see I had the blocked decked but made sure the stamping pad wasn’t touched.
Having an explanation on this makes a big difference on the value of this block.

Take a clear high resolution pic of the whole pad after you clean it off with lacquer thinner on a rag. Then send to me full size.

[william]

The Z character isn't the problem.

[bcmiller]

Agreed.

I still want to see the full pad. You can send to me if you want.

Engines were definitely being restamped in the 80s, and probably some in the 70s.

[boomer632]

This is one of them

[jeff400w]

bcmiller , I’ll clean up the pad and see if I can get a better picture.

[bcmiller]

bcmiller , I’ll clean up the pad and see if I can get a better picture.

Sounds good.

[firstgenaddict]

Is that a 386 block?
I don't have a problem with a GRIND OUT and gang stamped over the grind out - it's the errant skewed Z which is difficult to explain.

[bcmiller]

Is that a 386 block?
I don't have a problem with a GRIND OUT and gang stamped over the grind out - it's the errant skewed Z which is difficult to explain.

From his original post.

You can see I had the blocked decked but made sure the stamping pad wasn’t touched.

[firstgenaddict]

I can see the marks on the pad from being ground out with a rotary abrasive wheel.

They run approx in the direction of intake to exhaust

There are NUMEROUS examples of these (grindouts using a rotary tool and either hand or gang stamped) on low mileage never apart Corvettes.

The problem here is because it was decked there are no broach marks ANYWHERE, which makes the whole thing MORE QUESTIONABLE.
If I were writing a report for a customer. I would state that the pad has no broach marks visible and does not represent the typical characteristics of Assembly line deck stamps. I may indicate the appearance of a grind out, however with also being decked determining exactly what has happened very unlikely and would not be able to make a determination whether or not the engine was a DZ from the factory. 

[jeff400w]

Here is hopefully a betting picture. As I have looked more closely at this stamp it does appear that the stamp had been ground off and restamped. If  you look closely under the 4 and the D you can see a DZ.
Yes it is a 386 block Cast H 28 8

[bcmiller]

Does look like a grind out. Will let others chime in.

I could be wrong, but I am leaning one direction.

[jeff400w]

Bryon,could you see the DZ underneath?

[dannystarr]

I see what looks like part of a D and a Z  ??   Danny

[dannystarr]

Original

[dannystarr]

I see what looks like part of a D and a Z  ??  Maybe a V also to the left? Danny

[firstgenaddict]

I will say I have fewer issues with the stamp now that the photo is clean and crisp and square.
The Vin Stamp exhibits many of the same characteristics as other early vin stamps at Norwood, characters/spacing.
IMHO the faint stamp looks like the gang was misloaded, it appears there are too few characters.
 Maybe? V9ODZ ?
I can make out the V and the round tops of two numbers before the faint DZ.
 

[Mike S]

 I remember an old thread like this topic and John Z's reply (#23)
http://www.camaros.org/forum/index.php?topic=8417.msg58199#msg58199

Mike

[bcmiller]

Bryon,could you see the DZ underneath?

I see it.

Can you provide the block casting number and casting date please?

[David K]

It looks like a restamp to me. I actually think the 04 is not part of the underlying stamp. When I get home I'll look at it on a big screen and post what I am referencing

[Jerry@CHP]

I have documented one factory grind out on a '67 Z28 in which I knew and worked with the original owner back in the 1980s.  I have photos.

Jerry

[jeff400w]

It’s a 386 block, Casting date H 28 8

[bcmiller]

I know there will be some that won't agree, but based on what has been presented here and what I know...

I am 75 percent sure the block stampings are genuine.

[David K]

Clearly restamped, but that’s just my opinion.

[bcmiller]

Clearly restamped, but that’s just my opinion.

Restamped - YES. But do you understand what a grind out and a FACTORY restamp are?

[rocco376]

Grind outs have been discussed numerous times on various Corvette forums.  I can't remember which car it was, but there was a C2 Corvette recently on Bring A Trailer where it was discussed in the comments.  The Seller posted a weird letter from an alleged assembly line employee at the time talking about factory grind outs and how a different type of grinder was used on small blocks vs. big blocks.  Can't find the correct auction but will post the letter if I locate it.

[Badshifter]

Out of curiosity and lack of knowledge, where on the line would this grind out have taken place? When the engine left the assembly Plant, it only had the engine designation number on it and not the Vin correct? If the Vin was mis-stamped on the assembly line would they have not just ground out the Vin and re-stamped that?

[David K]

For reference sake I copied the others from the referenced post. I am wondering if whomever was restamping forgot the Z and realized it, grabbed it and hammered it. I’m good with the stamp, but it’s my opinion. It was already a DZ…

[GMAD_Van Nuys]

Information about correcting VIN numbers stamped at the Norwood and Van Nuys assembly plants:

https://www.camaros.net/threads/factory-restamping-vin-on-block.24850/

[bcmiller]

For reference sake I copied the others from the referenced post. I am wondering if whomever was restamping forgot the Z and realized it, grabbed it and hammered it. I’m good with the stamp, but it’s my opinion. It was already a DZ…

In this case we are talking about a POTENTIAL factory grindout and POTENTIAL factory restamp at the engine plant.

[David K]

Yes we are. There's only 1 or 2 people who would know.

[black69]

I myself do not see a confirmed DZ below the top stamp.  It could be a part of a 0 for the assumed D.
I think the V is fairly well defined and thus, the 4 numbers for the build date would push the underlying DZ to the right of the above stamp.  Lots of odd things going on here. 

A magnaflux could maybe help determine what is really below the grindout.

My 2 cents.

[Jonesy]

I dont mind the partial VIN stamping, but the rest of it does not add up to original DZ early Sept 68 stampings. Only guys with numerous stampings of this time period would know what Im talking about.

[bcmiller]

I dont mind the partial VIN stamping, but the rest of it does not add up to original DZ early Sept 68 stampings. Only guys with numerous stampings of this time period would know what Im talking about.

I know what you are talking about.

It’s just an opinion, but we would not be seeing what you are talking about if it was done in the repair section with a grindout.

[KurtS]

A repair would not necessitate a grindout. Only a misstamp on the engine assembly line, which logic says would only be the first or last engine of a batch.

[bcmiller]

You all may be correct. I don't know and I don't know if there will ever be a full answer.

The stamping that was wiped out appears to be V09DZ - they did not have the day in there. I believe the grind out would technically be called a repair, and would not be handled in the same general engine assembly area.  Could possibly have been messed up on Monday - second day of the month, then fixed on Wednesday - the fourth day of the month.

Do we have anyone that worked in the Flint engine plant that might know how things like this were handled?  Tonawanda might not be the same otherwise we could ask bergie.

[boomer632]

Looks like a flap wheel was used to grind out.
Were those around back then?

[bcmiller]

I am not saying it is for sure genuine, but possible.

[KurtS]

Grindouts are seen on Corvette engines - they used the low volume line and had lots of low volume engines. So the engine plant was switching between models regularly and you could see how they could mess up the model changeover every once in a while. Where as pass cars were much higher volumes and changeovers didn't happen as often and grindouts are rare.

[firstgenaddict]

The chattering look of the grind out appears exactly the same as the grind out and restamp on my brother's 30k mile survivor 1973 Corvette L82.

I have some 1970 ZR1 grind outs which you would laugh at (just the last letter dished out).
Most of the ZR1's were converted CTU LT1's which already had the larger oil pans.

Seems in 1971 -72  they would gang stamp all but the last suffix letter (especially late in the year) so the engine application could be SET after build up WITHOUT grinding out.
EX. from my 71 LT1