Matching numbers or not?

[Dennis T.]

I recently purchased a 1961 Corvette. The car had a complete frame on restoration in 2001. The engine was rebuilt and they had to "deck" the block, which removed the numbers from the front pad on the engine. However, the information I have confirms this is a 1961 Corvette motor from the numbers on the bell housing. I had an individual tell me this can never be considered a "numbers matching"motor due the lack of numbers on the front engine boss. Another, however, disagreed. What is correct?

Also, I've been told there is a chemical that can be placed on the front pad that may reveal the original numbers, if the decking procedure was not too deep.

Finally, can the front numbers be legally restamped on the front boss under either scenario?

The car has the original T10 transmission stamped 1961 and all glass is correct date except the windsheild.

[Michael W.]

Re: Matching numbers or not?

Dennis- welcome. I see it's your first post.

The term 'numbers matching' means different things to different people so it's not surprising that you got differing answers. Because it's become so hackneyed, many just avoid using this phrase or debating what the 'correct' definition might be. One definition I like is that 'matching numbers' means the seller's price matches that of the buyer. The phrase is never used in NCRS judging.

It's unfortunate that the engine builder elected to deck the block as it's simply not necessary 99% of the time. Many shops do it as a routine operation or to suit their own internal purposes. More unfortunate is that 100% of the time, the pad surface can be saved through careful set up and operation of the milling machine. The cutting head can be stopped short of touching the pad.

The numbers found elsewhere on the block may be correct for a '61 Corvette, but as far as I know, the same block was used in many other GM cars. This means that the engine in the car now may/may not be the original or from any Corvette.

Restamping is not illegal in most places but it serves little purpose. It will be detectable in almost all cases and frequently suggests some sort of attempt at foul play.

Hope this helps.

Mike

[Art B.]

Re: Matching numbers or not?

Dennis:
Your post caught my attention because I have a '61 that had the engine block decked some time before I purchased it. Fortunately, most of the numbers on pad were still faintly readable. I have had the car judged at a Regional meet and it received a top flight. No deductions were made on the engine pad. The problem you may have is that the original broach marks have probably been erased in the decking process which will result in some deductions if you have the car judged.
The issue of restamping the pad is your decision. Unless you are planning to go through the judging process, I would not worry about it. I concur with Mike's comments.

[Terry D.]

Re: Matching numbers or not?

Dennis
Agree with other post if you are not going to have it judged what do you care? If you plan on the judging route then you need to do a lot more research into what "matching numbers" means. What is the build date of your car? Do the casting dates on the motor, tranny and rear end fall into line? Is there a matching vin number on the tranny? How about generator numbers? Voltage regulator? How about the frame? Are the carb and manifold correct? I think you now see that there is more to a matching numbers car then just the stamp pad.

[Ken R.]

Re: Matching numbers or not?

There was a Restorer article many years ago about Ind. state police using a method to recover the engine stamping. I am sure if you Google this you will find info on the method. It was using heat/cold to reveal the numbers or such. The metal under the original numbers is harder than surrounding metal so the method brings the old numbers out as I remember.

[William F.]

Re: Matching numbers or not?

Tell your engine builder/machine shop he owes you the $10K he just removed from the value of your car, at least to those who do want be able to reasonably prove the engine was original to car.

[Dennis T.]

Re: Matching numbers or not?

Mike:

Thanks for the help. Think I will try the chemical on the front pad to see if it will bring up the numbers. The only info I had on the bell housing casting numbers indicated it was a corvette engine. Now I will check for other GM engines to see if they also used those numbers.

Dennis

[Dennis T.]

Re: Matching numbers or not?

I see what you mean, not that interested in all that, the trans appears correct and I will check date against manufacture date on id plate. I just enjoy driving it and having fun.

Thanks

Dennis

[Dennis T.]

Re: Matching numbers or not?

Ken:

That's what I've been told. Think I'll give it a try.

Dennis

[Dennis T.]

Re: Matching numbers or not?

I'd like to, but previous owner had restoration done in 2001.

Thanks

Dennis

[Dennis T.]

Re: Matching numbers or not?

Art:

Thanks- I'm going to try the chemical id.

Dennis

[Joe L.]

Re: Matching numbers or not?

Art:

Thanks- I'm going to try the chemical id.

Dennis

Dennis------


The process you are referring to is generally a FORENSIC technique which uses an acid. However, and most importantly, this process does NOT restore the numbers---it just makes the stamping marginally readable for a relatively short period of time. So, I really don't know what good this process is going to do you except, possibly, satisfy your curiosity as to whether the engine is original to the car. It's not going to result in anything you can "take to the bank" or anything that's going to be useful in the judging process.

[Paul D.]

Re: Matching numbers or not?

Dennis, unless you have a resource that will perform that operation for free, I would check the casting DATE and compare to car's build date to see if you have a possible combination before spending the money. If that checks out, as Joe said, You will then get the satisfaction of knowing it is the original engine if the process produces favorable results. However, it would still "judge" as a restoration engine as per the judging guide, restamped or not. Chip.