QUESTION ON A POSSIBLE RESTAMPED PAD

[Marc N.]

how can you tell if your engine pad is a restamp or if it is the original and not played with.... being that the engine pad number matches the car?
thanks

[Tom H.]

Re: QUESTION ON A POSSIBLE RESTAMPED PAD

Either look at hundreds of stamps for years, or post a shot of it here for an opinion. If you are not sure, have a local chapter group have a look and offer an opinion. Is there something on the stamp that makes you suspect ? What year and HP configuration are you dealing with. Sometimes low horsepower small blocks aren't as prone to the stampers as the desirable high HP versions and big blocks.

[Jack H.]

Sometimes you can't...

If the restorer and 'stamp artist' have done top drawer jobs (preserving and/or duplicating broach marks + using correct/original font/placement), it's simply impossible to distinguish a well done 'restoration' block from the factory original. What generally gets 'caught' are the 'hack' jobs done by those with less than expert experience....

[Denny J.]

Re: Sometimes you can't...

Jack
could you tell if there was a valve job do to the car.Harden seats,Do they remove the stamps when decking the heads.Denny72

[Tom H.]

Re: Sometimes you can't...

Denny, when milling the heads, the numbers on the block aren't in any danger. The numbers appear on the block surface near the head mounting surface.

[Jack H.]

Re: Sometimes you can't...

You're not going to be able to detect subtle internal differences in engine components like the presense of hardened valve seats. That requires MAJOR component disassembly and visual inspection...

On do 'they' remove the stamps when decking the heads, I think we've got a terminology mis-match. There is a term 'decking the lid' that refers to machining the top surface of the block to regain a flat/true fit for the cylinder heads to mount onto. But, the bottom side of the cylinder heads simply can't be seen when the heads are installed....

On the block, the typical practice with machinest unskilled in the art of working on factory concours engine jobs, is to true the top side of the block using a circular mill and this WILL remove metal + some degree of the factory original stamp pad surface repleat with its stamped numbers and broach marks. There are ways around this and they require close supervision of the machinest and/or the addition of time and $$$ to the engine 'restoration' process.

The simplist case is when you have the factory original block for your car. There, you simply INSIST that the machinest NOT deck the lid and preserve the original stamp pad marks. In most cases it can be done, but once in a while the years of thermal stress/strain simply dictate the upper surface has to be trued for a solid rebuild.

In that case (OR the situation where the original engine grew legs and walked away under prior ownership), the restorer is left with a decision. To what level of time/effort will he/she go to make a good 'restoration' motor?

If it's the factory original block and it HAS to be trued, then good restorers will take photographs and document the situation. They'll let the upper surface be trued and send the bare block out to one who provides a broaching service (re-create the appearance of the factory original marks left in the stamp pad by the broach machine).

Last, they'll seek the services of a competent stamp artist to recreate the original numbers. This is a guy who's invested HEAVILY in acquiring custom stamp dies over the years to match this particular zero, that specific five character, Etc. where the font was obtained from untouched car/truck blocks over the years.

He'll go to his stamp inventory and replicate the original characters used, load his gang stamp tool (some specific era stamp jobs were done either without a gang tool and/or stamped in multiple passes, but that's where the experience of the stamp artist comes into play) and lay down a copy of the original number sequences in the exact postion(s) they were in originally.

The same process goes for those seeking to re-create the appearance of a factory original block where they don't have the original to copy from. In this case, the donor block is broached and stamped based on the stamp artist's personal library of similar engines built in similar time frame. Either way, you get a block that 'appears' to be factory original and that's the extent judges go to at NCRS and/or NCCB/Bloomington...does it appear to be factory original.

There are other caveats involved like finding that across-the-counter bare block service spare with real McCoy broach marks and a BLANK stamp pad. There's also the case of starting with a passenger car/truck block that's virtually identical to the Corvette block but has a shorter suffix code (e.g. a "D" meaning 283, 2-Bbl carb + powerglide transmission) that's extended into a full Corvette suffix code (like "DG" for a 283, 4-Bbl carb + powerglide transmission).

So, there are numerous ways to satisfy the visual inspection of judges in the restoration process. BUT, a Corvette only has its original motor once! Any deviation(s) from the real McCoy item, result in a 'restoration' motor. That fact should be disclosed by the owner...

And, yes there are the unscrupulous out there who take the opportunity to make their car into something that GM didn't actually build... Yes, they'll use the same proceedures. And, yes, this is a WRONG DOING, with morale and ethical consequences. But, do we catch them all? Sorry, Charlie...that's the fact(s).

[Denny J.]

Re: Sometimes you can't...

Jack GREAT answer
Marc print this answer
Jack covered all the bases.
So it is all down to "Documentation"
AND!! the importance of a Original unrestored car is.
INFO
and thats why I get a kick out how many "NEW" 1967 427/435hp are out there.
Denny72

[Barbara S.]

Re: Sometimes you can't...

I'll ask a question that will probably seem like herasy in here: if a re-broach and restamp is SO GOOD that it passes judging, then why is restamping such a bad thing? The other standards in NCRS judging are based on appearance. Does the car's attribute APPEAR to be original? If the stamping pad APPEARS original, what difference does it really make if it is or isn't the original? Nobody is the wiser anyway.

Tony

[Warren F.]

Re: Sometimes you can't...

Not a thing. Until it is represented as something other than the way it was configured originally.