My original, numbers matching engine, from my '76 L-48, is sitting on a stand in my basement, just incase the next owner wants it.

I don't think it would be worth the time, effort, and money to restamp an engine of this type.

 

On a good day, my socks match. Expecting more than that out of me is a risky proposition at best.

Yes, we go through this every several months, and yes, it's kind of boring. But what never really gets discussed is who is responsible for all the re-stamping that goes on? IMO, it is the folks who propagate the irrational belief that a 40 year-old car that still has the engine block it left the factory with is worth substantially more than a car that has some otherwise identical block in it. Take the profit out of re-stamping and I'll bet the practice will stop in short order.

 

Maybe, I should have just posted a thread titled "How to Identify a Re-Stamped Block?", and left out the behind the scene's story.

I have read lots of opinions....but no help here thus far....I will try the C-1 / C-2 threads as suggested by VB. Thanks

 

I'll make a bold statement that probably 95% of restamps can be identified in a decent photograph or at arm's length with a flashlight. The remaining 5% that were done by a professional or a lucky amateur can increase the pucker factor considerably.

Although the stamped characters are relatively easy to duplicate, the surface of the pad is not. Do a search on 'broach marks'. Very few restampers get the pad just right, or are unaware of the importance.

There's a gentleman by the name of Al Grenning who has raised the art and science of stamp pad research to a whole new level. He maintains a huge library of pad photographs and 'rubbings' to allow him to compare a given pad to engines that were installed just after and just before the one in question. If the pad bears no resemblance to it's siblings, it's fair to start asking questions.

Bubba wouldn't stand a chance.

 

1. How many of you out there swear that you have the original engine in your car, but in fact you may not and there is no way to prove it.
2. What if it was restamped 6 owners ago and was sold down the line as 'numbers matching' then the next buyer finds out about a restamp.. where is the fraud and who pays? This forum is littered with people who 'found out' after the sale and did not even look at the car before buying or did not look at the stamp. even if they did, 95% of buyers out there just want a muscle car and have the money and just look at the numbers stamped at best..
3. just because it is restamped, does not mean that it is not the original engine.. happens all the time.
4. great on the broach marks, but the best of the best can do the broach marks also.

if you want to remove your engine, ship it several states away to one of the best restampers, have them stamp it for a 4 figure fee, then ship it back and put it in your car, then go ahead.. the money and effort it costs you pretty much defeats the increase in value to your car, and the risk you will take in selling it. Now if you do it to pass points in NCRS, then you are indeed willing to play that game...

 

It's interesting that there is a specific govenmental procedure for replacing the odometer in a car that includes documenting at what mileage it was done and not to set the miles on the new odometer to match the old one but no such procedure for replacing the engine.

Yet, in Kansas, any car coming in from out of state must be checked by the highway patrol to make sure it is not stolen. They look at the VIN on the engine and on the chassis.

I guess as long as the chassis VIN does not come up stolen they don't care if the engine was replaced.

cc

 

Very good point. People have engines rebuilt and the dumbsquat rebuilder decks the block even tho we told him not to. So you put the numbers back on but the finished product looks worse than the worst amateur fake/restamp you have ever seen.

 

I swear that the engine in my Exploder and my wife's Camry are original. I know because we bought them new. If you asked me to prove it was the original engine, the only thing I have to offer is my word. If you think I might be a liar, then I have no proof at all.

Don't even get me started on "documentation".

 

This is when you call in the big guns if there is sufficient interest and money at stake. No different than in the fine art or high end jewellery game.

 

All Chevy blocks, big block and small block were cast and machined ( Broached) at a foundry and stamped with the date and engine code prior to shipping to the specific assembly plant. Then weeks, and sometimes months, go by prior to installing the engine in a particular car and the vin derivative is stamped then.

A 454 or 350 block is cast that may or may not go into a corvette. ( Usually not, since they made so little corvettes compared to trucks, impallas etc..) It may go into a truck, chevelle, impala, or any other chevy... and there may be hundreds machined between each corvette block. The little trick of reviewing broach marks between Vin #s before and after a corvette in question is just not practical. The block surfacer/broach blades may be sharp or dull, resulting in various broach marks. There is no valid proof that this should be an authenticating factor . only VIN Derivative #s can be scrutinized, not broach marks or date and engine code stamps. Sure there may be nuances where corvette blocks are singled out and machined together.. but that is heresay too.

These authentication services that charge 4 figures are just insane. Vin # x and Vin # X+1 may have totally different broach marks because they may have been surfaced hundreds apart from each other.

Sure the Pad database is pretty cool and took years to compile.. but it is full of old photographs and rubbings? Only recently in the last few years has high megapixel cameras been available to really look deep into a stamp and subsequently stored into a database…

These guys won’t tell you this.. they will say they have thousands of photos from this great database, and will compare your stamp to their database and give you a ‘best guess’ . when in fact they will still take your money and only tell you ‘maybe’.

Bottom line is, there is no way to know if you have the original engine in your car unless you are the original owner. And if I was buying a car from that original owner.. and he wanted an original engine premium price , I still might not believe him.

95% of people don't know and will not even look at broach marks or casting dates, or stamping fonts, or engine codes and dates, or other drivetrain parts.... they only look at the Vin derivative numbers. Then they get the car home and later cry foul. I know, I made that mistake once, but I learned alot and will not make the same mistake again.. If I was looking!.


IMHO

 

Let me throw this out. Magnafluxing the block. The old stamp should show through, especially if they off set the new stamp.

 

I see you've misread my post above and gone on a tangent. Unless you've been present at one of Mr. Grennings presentations and are directly familiar with the level of service and attestation he will provide, you might want to withhold making further assumptions.

 

Now here is an idea.....As I am a certified Level III NDT Inspector / Examiner, RT, UT, MT, VT, & PT....I would be very interested in any results from other's. It would have to be done with skill and repeated applications ...but I think if the indentations are there...they will show. Thats not to say you can see the original numbers clearly...but, it should show a stamping indication / shadow of the original stamp over lapping the re-stamp. This however is all dependant on the amount of material removed upon decking. A light acid etch would enhance this process.

Sounds great...but, I doubt anyone in here would be willing to go this far. For the high end guy's with car's that are suspect, this could be the the answer you are looking for.

I am just looking for the the tell tale sign's that would say.... AH HA!....What do we have here?

 

Over decking to really remove all traces (odd grind marks) would be a good sign also. I am sure they would nick here and there (other block surfaces). If you think like a numesist (coin collector) I am sure you could catch the tell tales easy enough. Paint might cover up small touches but a good whack will show even through the paint. At that point if I seen any of those I would 100% dismiss any credibility to what the block really is or was. Since more than likely it’s not what it is being represented as or it would be clean right?

 

Magnaflux will show up cracks/voids and areas that disrupt magnetic lines of force. I don't believe that areas of higher hardness or surface stresses will become visible via Magnaflux. However, a nital etch of the bare surface may show some surface imaging of areas work-hardened by stamped numbers...if not ground off very deeply.

The CSI TV shows will no doubt have a process that will evoke those original numbers...as well as produce the finger prints and DNA profile of the machinist who milled the block.

 

I have been to Al's session. Very informative and an eye opener. One comment though. If I had a stamping that wasn't cookie cutter, like a BB that came off the passenger car line because they ran out of Corvette blocks at the time (it happened) and they ground down and restamped this block at the factory but yet it's in fact the original block to the car and I get an attestation that it is original. I may believe it having paid decent bucks for that, but I doubt the next buyer will. And that is just one example of the many that were provided of the non-typical type of stampings that left the factory.

 

Joe, that's a very good point but factory grind outs are not that rare and are part of Al's research and documentation. A skilled inspector will take this into account.

All I'm saying is that Bubba quality restamps are easy to pick out by an interested observer. As the quality of the potential restamp goes up, so does the need for diligent inspection and research. If I were in the market for another car and was about to pay a premium for a supposed factory original untouched engine, I'd seriously consider having someone more educated and skilled than myself involved.

 

it is still a question of these guys taking your money and telling you what you want to hear.. just like appraisers, they will put just about any price down if you pay them enough.. but if you look at the fine print in the back, they are absolved of any liability. any authentication service does the same.. they will have their disclaimers required by their lawyers written in small print.. What can they attest to? they still cannot reasonably guarantee anything. And if they do, one should then realize what pit his money is going. This is still just like the NCRS, they do not authenticate, they will only tell you if it appears factory original.

The best of the best fakers vs the best of the best spotters battle. I understand that these guys go against each other very rarely.. alot more in the C2 world..

Yes bubba restamps are pretty easy to catch and is exactly what you see 95% of the time... but if you are really going to play the game, it costs big bucks and you still get no guarantee...

I think these authenticators using broach mark arguments and factory grind out and restamp issues, and whether the stampers ran out of '1' and used an I, or had a drunk factory worker misallign the tool, overdecking, or any other possible scenario given or submitted, can not attest to anything. it would only be a very educated guess. and they charge alot of money to do that.

just trying to warn all you folks out there what you are getting into if you decide to play the game.

 

I owned a 1969 Camara Z28, all original back in 1971. I had a spiroloc work its way loose and scored the heck out of the #3 cylinder wall. To save the block I had the cylinder sleeved, then all 8 bored .020 over.
The block was decked as lightly as possible to save the vin #.

Now the $64000 question:
How would you sell the car, original block, repaired block, or?? You guys tell me

 

its still the original block. if #s are visible thats all that counts.