Ground down serial numbers

[knish71]

A friend of mine and I need an arguement settled. Another friend of ours owns a 1972 Corvette. The serial numbers have been ground down and restamped. When purchased from the previous owner, he was told that the numbers totally matched and the restamped block was done at the factory. My friend says that the factory at times had restamped blocks in this manner before installation for one reason or other, and I agrue that because I've never heard of such a practice, it must not be true. Anybody out there with information that can support either side??

 

[tonyk72]

I have never heard of such a practice...but that doesn't mean it didn't happen.
Was this a restamp done at the factory during assembly? I guess that may be possible, but if it was done afterwards...I doubt it. I'm just guessing though.

Edit

Ok, I flipped through my NCRS Tech guide...it says:

"Tonawanda is known to have salvaged cylinder cases from failed engine assemblies & retsamped the cases. St. Louis has ground & restamped serial number identification."

 

[mauivette]

CorvetteMagazine.com has an excellent article on matching numbers. Check it out.

I guess it could'a happened................. But I doubt it.

 

[Vettehead Mikey]

I'm afraid your friend is right. There's many, many documented cases of factory restamps. Al Grenning routinely displays photos of these during his stamp pad and documentation presentations. Attend one if you can. One of my local chapter members is the original owner of a 66 427/390 coupe with such an engine.

The problem with any restamped engine is who did it, when, and why.

 

[knish71]

Really.....How do you think one could ID a factory restamp versus someone grinding down the serial numbers trying to pass one off as an original motor?

I have never heard of such a practice...but that doesn't mean it didn't happen.
Was this a restamp done at the factory during assembly? I guess that may be possible, but if it was done afterwards...I doubt it. I'm just guessing though.

Edit

Ok, I flipped through my NCRS Tech guide...it says:

"Tonawanda is known to have salvaged cylinder cases from failed engine assemblies & retsamped the cases. St. Louis has ground & restamped serial number identification."

 

[knish71]

Mikey, do you know a way Al Grenning could be contacted? My friend is very curious about his predicament and would like to consult with him.

 

[knish71]

Tonyk72, Is there any reference on how to ID such a restamp? Is that document you're reading from online, if not, how could I obtain that NCRS Tech Guide?

 

[JohnZ]

Mikey, do you know a way Al Grenning could be contacted? My friend is very curious about his predicament and would like to consult with him.

Al's e-mail is ALGRENNING@aol.com ; he'll need several close-up (macro) high-resolution in-focus digital images of the pad (with no paint on it), plus some other info, to evaluate whether your friend's block is a factory "grind-out" or an obvious re-stamp. Al has over 7,000 macro images of Corvette block stamp pads, and knows all the production variations and anomalies, almost by the day. He won't be home this weekend (NCRS Speedway Regional Meet at Charlotte).

 

[tonyk72]

Knish, here ya go...I was referencing the 70-72 NCRS Technical Information Manual & Judging Guide. You can order right from the souce @ http://ncrs.org/store/shop.cgi/page=C3.Library.htm/SID=1082076028.10342
Full of detailed info, well worth the $$$.
As for identifiying a restamp, you could possibly eliminate the possibility of a "factory" restamp if the stamp pad has arch shaped swirl marks. For example, if I were to take my 3/8" drill with a circular sander attachment and start sanding the pad...although I'm not 100% sure if the factory restamps could have possibly done it this way too.

 

[knish71]

JohnZ, Thank you very much for Al's email address. We'll definately take the best close-ups as possible and send them off to him. Thanks to all.

Al's e-mail is ALGRENNING@aol.com ; he'll need several close-up (macro) high-resolution in-focus digital images of the pad (with no paint on it), plus some other info, to evaluate whether your friend's block is a factory "grind-out" or an obvious re-stamp. Al has over 7,000 macro images of Corvette block stamp pads, and knows all the production variations and anomalies, almost by the day. He won't be home this weekend (NCRS Speedway Regional Meet at Charlotte).