"Factory" Grind out on Stamp Pad

**Jim L.** · June 28, 2009, 08:41 PM

Re: "Factory" Grind out on Stamp Pad

Originally posted by Rich Gianotti (38594)

The VIN is ground off in a way that you'd have to be blind and have no sense of touch to think it was ok. I mean, it is brutal.

So, would someone doing a resto in 1989 think they could fool anybody by grinding out a VIN? Why not just deck the thing and re-stamp the whole pad?

Rich,

I'm no expert on the engine assembly stampings. Keep that in mind. However, I would be inclined to believe you've got factory rework there.

Here's why....

Stored away in my barn, out of sight, I've got what I think is a genuine '61 Corvette base engine block. The VIN derivative on this block looks like it was applied by a drunk. Each number was individually stamped. Each number exists on its own horizontal line. Each number has its own individual angle of tilt. It's a mess.

I've never offered it for sale or even tried to find the owner of the car for which this block is probably original. Why? Because it's a mess and convincing anyone that this is a factory screw up would require more effort than I'm willing to put forth.

Your engine sounds similar.... if perhaps slightly worse. And I believe that's factory rework you are seeing.

Jim

**Terry M.** · June 28, 2009, 09:13 PM

Re: "Factory" Grind out on Stamp Pad

I don't know what was happening at Flint or St. Louis in 1961 or 1969, but when we had the National convention in Warren, MI, some of the attendees were able to tour Flint engine. This would have been likely a decade and several decades after your engine(s) was/were produced. Also this is about the the engine assembly stamp position -- NOT the VIN stamp position at St Louis.

A bunch (perhaps 6 to 10) of us asked the guy swinging the hammer at the Assembly Stamp position what he did if there was a mistake. He took a large hand held die grinder out of a drawer and plugged it in to the air supply. The next engine to come up he applied the die grinder to the pad with vigor. As we all looked on in horror he proceeded to stamp the assembly information to the rough surface three or four times. He did the same multiple stamp to the next engine to come to his station.

We all left there quickly, before the next engine came to him. He was laughing as we departed. Since he had the hammer, I thought it best to remain silent about his sense of humor.

Could the same sort of event, using similar tools, happen at St. Louis? That is the challenge -- to identify typical factory production, and to decide if what you have is typical or atypical.

**Terry B.** · June 28, 2009, 09:48 PM

Re: "Factory" Grind out on Stamp Pad

Rich,

If I were you, I would contact Al Grenning. Al has photos of hundreds if not thousands of example of stamps pads and some that might help support you that yours is an original. He may also put the whammie on it too. He has studied stamp pads for a number of years and is the NCRS authority on the subject.

I do not have a number or email address for Al but I'm sure someone on this Board will know how to get in touch with him. I believe he advertises in the Driveline too.

Terry

**Jim C.** · June 28, 2009, 10:08 PM

Re: "Factory" Grind out on Stamp Pad

Rich,

This may not be exactly what you're looking for, but as the owner of a 1966 Corvette with a less than perfect pad, you may take some comfort in my response. My "pad problem" deals with the motor assembly stamping. The VIN derivative stamping on my motor is fine, but there are clearly two individually stamped characters on the assembly stamping, which reads "F0726HE." The F0726 part is fine, however, the H and E characters were individually stamped and both double struck to boot. They don't line up with the other characters (F0276) and are clearly spaced differently.

Well, that sort of bothered me, and I've received some skeptical looks from other Corvette owners and one NCRS Judge during flight judging. In an effort to show that the motor and its stamp pad are ORIGINAL and correct, I did some research and spoke to past owners all the way back to 1975. None ever had the engine re-stamped, and one owner had photos of the pad from 1986 when he earned Top Flight without any questions asked. It still looks the same today. That still wasn't enough for me, so I did more research and found a pretty nice article in an old copy of the Restorer magazine (Fall 1994) by Al Grenning. The article specifically addresses broach marks, gang stamps, double strikes, etc. etc. and GRIND OUTS. The grind out section might be what you need to read. The article seems to apply the "grind out" application to the motor assembly stamping, but I guess you could apply the same rationale to the VIN derivative too. Basically, they did occur at the factory, as did individually stamped characters, double strikes, etc.

Maybe contacting Al Grenning might help too. He might be able to provide more information. I suspect that your stamp pad is probably okay. But remember, you're ALWAYS going to have a few "doubters." There's nothing you can do about it. Just enjoy your Corvette. Happy driving.

Jim C.

**Jim C.** · June 28, 2009, 10:24 PM

Re: "Factory" Grind out on Stamp Pad

Rich,

One more thing to think about. I'm not 100% sure, but Mr. Grenning might charge you a fee for tapping into his expertise. I had questions about my pad, as described in my previous post, so I contacted him, and he was more than willing to give me his opinion. However, it was going to cost me a few hundred dollars first. I think if you ask him to "affirm" your pad, he will charge you for the service. Maybe it's worth it to you, maybe it's not. You'll have to decide. Good luck.

Jim C.

**Rich P.** · June 28, 2009, 11:12 PM

Re: "Factory" Grind out on Stamp Pad

Rich,

I know of a 72 Targa Blue L-T1 coupe 100% ORIGINAL UNRESTORED from the original owner whos vin (not the build date) was ground and restamped. at St Louis There have been several documented cases of this.

Rich

**Edward M.** · June 29, 2009, 05:50 AM

Re: "Factory" Grind out on Stamp Pad

I recall seeing something like this on a yellow 68 around the 1989 time frame. Pretty sure this was at the Williamsburg, VA regional meet. I am thinking it was a 400 hp car, but I could be mistaken.

The grind out of the VIN was ugly. There was lots of speculation about that pad. Looking back on it, I am inclined to believe that this was an original "mistake".

**Terry M.** · June 29, 2009, 06:05 AM

Re: "Factory" Grind out on Stamp Pad

I remember a 1969 and a 1970 at Joplin in seperate years back when I was NTL. Real ugly pads. Al pronounced the 1969 (a red/red 435 no less) the real deal, but that was "back in the day" as we say. I think the 1970 was before Al's time.

**Rich G.** · June 29, 2009, 06:06 AM

Re: "Factory" Grind out on Stamp Pad

Thanks for all the comments. I did contact Al when he started his service but I never followed up, mostly because his literature said he needed the car on a lift, and I don't have that ability. I could always work a deal with the local service station, but it got too complicated so I never followed up.

It really doesn't bother me, I love the car and it's great to drive, but once in a while I think about it, like last night.

I will eventually contact Mr. Greening and get his opinion. How ever it comes out, I won't have a problem with it. I think it would be nice (and only fair) for the next owner (many years from now!) to have an expert opinion.

The car was judged several years ago at a small chapter meet The judges did have a problem with the pad. I had just got the car and really had not noticed it before that, mostly because I never looked closely. I knew the car and its history and never thought anyone had messed with it.

One of the judges thought it possible that the motor that was in the car now could have been found by the restorer with a proper assembly stamping, but with the wrong VIN, and then the restorer did the grind out, hoping to make us think it was a factory re-work. I suppose anything is possible.

Rich

**John D.** · June 29, 2009, 06:49 AM

Re: "Factory" Grind out on Stamp Pad

Terry McManmon's recollection from the Flint engine plant tour is right on. Shortly after that early 90's NCRS national event Dr. Mike McCagh invited the assembly line worker to his farm to put on a seminar for a large group.

We once again heard that same thing Terry said. Grinding off engine pads with a small grinder that the worker had hanging from tool belt was quite common.
At a recent seminar that Al Grenning put on for our Pittsburgh chapter, etc Al took a different approach for all of us. Instead of showing us pad that looked 100% dead nuts he showed us a ton of engine pads, trim tags, etc that were in fact the real deal but few would recognize them as such. Not typical for sure. Be very careful before you discredit a tag as being a fake. You may be looking at the real thing. JD

**Jim L.** · June 29, 2009, 07:30 AM

Re: "Factory" Grind out on Stamp Pad

Originally posted by John DeGregory (2855)

Be very careful before you discredit a tag as being a fake. You may be looking at the real thing. JD

John, you just brought back an unpleasant memory: Regional in Steamboat Springs sometime in the early '90s. I drove my unrestored, original engine, FI '60 to the event and entered it for judging. A pompous, self appointed expert pronounced the (unmolested and perfect) pad on my car's engine a re-stamp.

It's not.

That was the last time I let an NCRS judge anywhere near that car.

So, yeah, Guys, be careful about pronouncing anything about these cars as "fake".

Jim

**Wayne M.** · June 29, 2009, 08:15 AM

Re: "Factory" Grind out on Stamp Pad

Originally posted by Rich Gianotti (38594)

Is there any real info that exisits that would lead a rational person to believe that the factory would grind the VIN off a stamp pad and re-stamp it? ...Rich G

Rich -- here's a '65 big block from a 396 manual trans passenger car (cast E_14_5). Obviously done at Tonawanda as there's no earthly reason why a subsequent owner would do anything this crudely. You can see the broach marks that continue under where the cylinder head would be. My guess is that it was probably the wrong suffix (I can pretend to see and "IF", replaced by the LF

).

**Dick W.** · June 29, 2009, 08:36 AM

Re: "Factory" Grind out on Stamp Pad

Another one, 1971

Attached Files

1971 11882.jpg (39.0 KB, 409 views)

**John D.** · June 29, 2009, 09:02 AM

Re: "Factory" Grind out on Stamp Pad

The bottom line is there are more than a few cases in which factory grindouts have received full credit on the judging field.

"Factory" Grind out on Stamp Pad

"Factory" Grind out on Stamp Pad

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