Original Engine Block Decked

[Keith S.]

Is it possible to determine if an engine is original if the stamp pad has been decked?

[Tom H.]

Re: Original Engine Block Decked

Not really, although say there are some methods of "raising" the original numbers from a decked pad. Never tried it. Most likely if an original engine has been decked, you'll only have the casting date to put you in the "correct" category.

[Chuck S.]

Re: Original Engine Block Decked

Is it possible to determine if an engine is original if the stamp pad has been decked?

Owners selling cars with decked engines will frequently say, "It IS the original engine; I just had it overhauled and they removed the numbers in the process"...as if that is really going to make any difference.

Maybe the seller's word on this will comfort some buyers, but that decked engine will now judge exactly the same in NCRS as a properly dated replacement. Using the small block as an example, Flint made millions of them...without those pad stamps, it's just another small block and the value of the car is reduced.

Being able to discern the stamps forensically may be possible, but no owner will allow you that kind of access. As I said above, it really doesn't matter anyway. Your best option is to confirm all of the casting dates are, depending on engine option, within a month or two prior to the car's build date. If you find that to be true, it probably is the original engine...or a clever replacement.

[Larry M.]

Re: Original Engine Block Decked

Keith:

I would start by checking the engine casting number and the engine casting date. This may give you some clue.

If the casting number is correct and the date is a few weeks to a month before your car build date, it could be a good indication of an original engine.

You can also check the cast dates on a few other things like intake manifold, etc to see how well everything fits together datewise to your car's build date.

Larry

[Domenic T.]

Re: Original Engine Block Decked

I am following what you guys are saying and wonder how far ahead the heads were built. Can a may build date car have L ? 2 heads on the engine, or are the heads to early for the engine?

DOM

[Keith S.]

Re: Original Engine Block Decked

I appreciate the responses. For arguement sake let's assume that it's determined that the engine is original (one owner, original tank sticker, documentation from engine re-builder that engine was decked, owner's affidavit) and the car has a desirable engine. Is the car worthy of an NCRS type restoration and is it possible to obtain NCRS Top Flight status?

[Joe L.]

Re: Original Engine Block Decked

I appreciate the responses. For arguement sake let's assume that it's determined that the engine is original (one owner, original tank sticker, documentation from engine re-builder that engine was decked, owner's affidavit) and the car has a desirable engine. Is the car worthy of an NCRS type restoration and is it possible to obtain NCRS Top Flight status?

Keith------


As far as I know, an engine block with a blank or incorrect stamp pad but otherwise correct as to casting number and date receives a 25% point reduction of the points assigned to the engine block. I believe that it's very possible to achieve a top flight award with such an engine. Obviously, the car would have to do better in other areas than a car with a correctly stamped block to make up the points, but that should be very do-able.

[Chuck S.]

Re: Original Engine Block Decked

I appreciate the responses. For arguement sake let's assume that it's determined that the engine is original (one owner, original tank sticker, documentation from engine re-builder that engine was decked, owner's affidavit) and the car has a desirable engine. Is the car worthy of an NCRS type restoration and is it possible to obtain NCRS Top Flight status?

As far as NCRS judging goes, the rules have evolved considerably since I joined. Yes, as Joe says, this car will be a lot easier to Top Flight now than it used to be.

The problem is that sellers often want to get top dollar for such cars, and in my opinion, the price has to reflect the loss of the stamps, as well as the cars condition. The desirability of the engine option is going to play a big part, but the blank pad should give you some negotiating leverage. Keep in mind that a full restoration may cost you $30K or more...you'll have to decide if the buy makes sense, i.e. you'll need to figure how much you'll likely end up into this car, and be able to make some tenous, subjective estimates of future value (Good luck.)

I would still require statements from the owner and rebuilder. Those could come in handy later, but I doubt it will help you get ALL the engine originality points. Also, keep in mind that decking a block is sometimes the only way to save an original engine.

If it bothers you beyond the judging issue, stamp "restoration" is better accepted now. (I hear there are people that can do this well.) IF the engine actually is the original engine, and it sounds like that's likely, the tedious detail of finding a properly dated replacement is already done, and "restoring" the stamps has fewer ethical concerns. (It will still have to be virtually undectable, or you'll be worse off than leaving it blank. )

Frankly, beyond the judging issue, the loss of the stamps is only going to become important when you get ready to sell.

[Tom H.]

Re: Original Engine Block Decked

I am following what you guys are saying and wonder how far ahead the heads were built. Can a may build date car have L ? 2 heads on the engine, or are the heads to early for the engine?

DOM

Rule of thumb is 6 months prior to car build is acceptable.

[Chuck S.]

Re: Original Engine Block Decked

I am following what you guys are saying and wonder how far ahead the heads were built. Can a may build date car have L ? 2 heads on the engine, or are the heads to early for the engine?

DOM

Typically, engine casting dates will be tightly grouped because of the way GM built engines, but there are likely exceptions as well. All casting dates will, of course, have to meet the NCRS rule if they're visible.

As an example, my engine was built July 8, and the car was built July 30. The engine block was cast June 29, LH head July 1, intake July 2, RH exhaust manifold June 22. The LH exhaust manifold was a little bit of a flyer at April 21, but you get the idea.

I would want to check the heads as well, but an owner may not be receptive to removing the valve covers. In some cases, I think one head casting number (passenger side?) on some small blocks can be checked through the hole in the valve cover. If a lot of money is changing hands, and there is some anomaly, I would probably insist or no deal.

[Ronald L.]

Re: Original Engine Block Decked

In some distant lands they use an acid to reveal the cast iron micro structure and the original numbers/letters pop out. Never tired it, might find something on the web...

[Keith L.]

Re: Original Engine Block Decked

Same process is used in criminal investagations to trace guns that have the serial number ground off. Acid is ued and where the didgits were stamped the metal is more dense from the stamping process. The acid sometimes makes it readable. If I thought it was the original and was going to restamp it it would be nice to get the exact date of assembly and document that whole process. Granted it will still take the hit in value and judging.

[Joe R.]

Re: Original Engine Block Decked

I appreciate the responses. For arguement sake let's assume that it's determined that the engine is original (one owner, original tank sticker, documentation from engine re-builder that engine was decked, owner's affidavit) and the car has a desirable engine. Is the car worthy of an NCRS type restoration and is it possible to obtain NCRS Top Flight status?

Hi Keith:

Let's assume that it's the original engine with the correct casting number and a casting date within 6 months of the car's assembly date. The block was decked when the engine was rebuilt, and now there is no trace of any stampings or broach marks on the engine pad.

So how bad is this for NCRS judging? Not too bad at all. Out of the 350 points allocated to the block, the deduction would be 50 points for the missing numbers and 38 points for the missing broach marks, for a total of 88 points. The rest of the 350 points are tied up in the casting number and casting date.

Note that the 88 points is a so-called "standard deduction" that will be the same at any NCRS meet anywhere.

Given that the total points allocated to the car is 4500, this is less than a 2% deduction. You need only 94% to get Top Flight. So, the appearance of the pad is not a deal-breaker for Top Flight.

Also note that as long as you have the correct casting number and an acceptable casting date, it doesn't matter whether the numbers on the pad are simply missing or are present, but incorrect for your car. So, if you install an otherwise correct block from an Impala or Camaro (they made millions of those cars), you get the same 50 point deduction for the missing-or-incorrect numbers.

Interestingly, if the Impala/Camaro block pad has visible factory broach marks, you still get the 38 points allocated to broach marks. Thus, such a block would score even higher than a decked original block.

Pardon all the detail provided here, but I'm trying to make it very clear that the appearance of the pad is not a big deal for NCRS judging, since the points allocated to the pad amount to less than 2% of the total score for the car.

Your question asking whether such a car is "worthy" of NCRS judging pains me, because this is a common misconception about NCRS judging. The NCRS does not require a correct pad for Top Flight (or even Duntov).

The arena where people obsess over the appearance of the pad is for placing a market value on the car when it is being sold. Cars that have their original engines typically sell for higher prices. In this regard, the appearance of the pad becomes very important.

I think the confusion comes from the fact that when a car is being sold, NCRS experts are frequently called upon to provide an opinion about whether the pad is correct and original. While various NCRS members may have strong opinions about the significance of the pad when it comes to resale value, they must leave that behind on the judging field. The pad is only worth 88 points out of 4500 for the car, and that's it.

[Keith S.]

Re: Original Engine Block Decked

Joe,

Thank you for the very informative and detailed post as I very much appreciate you and the other members of this community sharing their knowledge to a less informed but very interested hobbyist as myself.

Keith

[Domenic T.]

Re: Original Engine Block Decked

Not really, although say there are some methods of "raising" the original numbers from a decked pad. Never tried it. Most likely if an original engine has been decked, you'll only have the casting date to put you in the "correct" category.

Tom,
Back in the midwest when they were stealing engines and grinding the #s off they used an acid to raise the #s.
I was told that they can raise the $s that are not covered under the new #s and try to determine if any match the ones from the car it was stolen from.
I have never seen it done as iot was done in a lab by law enforcement but can say that if they found your #s altered in any way you lost whatever the engine was in and faced charges.
I had a friend that bought a motorcycle and lost it that way when he was stopped for a traffic violation. He said his #s were stamped over to match the #s on the bike and that that was what was done in some states when you bought a used engine.
It took him 6 Months to prove his case and get the bike back and charges dropped.

Now how many here would have the acid brushed on their pad ?
All that would prove a fake would be the trace of an old #.

DOM