Welcome to the Corvette Forums at the Corvette Action Center!

#s matching engine locator.


Jan 16, 2002
1974 Red Convertible
My question is ; is it possible to replace an original #s matching engine with a non original #s matching engine and end up with a #s matching car? Do engines of the same model year match the #s of similar model years? I have heard of stories where engines have been found that made the car of the searcher a #s matching car. But it doesnt seem possible that one could find the original engine for a particular car.
IMHO this would be nearly impossible since the block casting date on the bell housing flange would have to be way off if the engine were from a different model year. Not to mention, the info on the stamped pad on the front of the cylinder case would also contain a code for the model year (or a derivitive).

I'll use my car as an example. The stamp pad contains the following info pertaining to the car itself: C11S106563. The first three characters break down as follows: C = Chevrolet, 1 = Chevrolet car line, 1 = 1971. The rest is unimportant in your quest as the year is part of the stamp. Even if the last 6 of the VIN matched, not much else would. The broadcast codes (i.e. CJK, CGZ, etc.) also varied a little from year to year so there's another inconsistency. Though the number stamping system evolved over the years, I think it would be pretty hard to accomplish a non-restamped match.

There are people who will restamp a block but thats another story for another time;).
Numbers matching is where the casting number, the casting date, and the stamp pad numbers are correct for the car. Since the VIN derivative is stamped on the stamp pad (and that includes the year) you cannot just pick one up that would create matching numbers. Only exception would be if the original engine could be found.

We really have two separate issues here. One is the term "matching numbers" and the other is a car with the original engine. The matching numbers term was originally used to indicate a car that had the original engine. A car can have only one original engine, that is the engine install on the assembly line at the factory. Once that engine is gone it can never again be an original engine car.

A matching numbers engine refers to an engine that has the correct numbers. The casting number, casting date, and stamp pad numbers, as stated above, are all correct for that car. It does not mean that it is the original engine. It is possible to take a car that has an incorrect engine, go out and find a block with the correct casting number and casting date, restamp the stamp pad with the correct numbers, install it in the car and call it "matching numbers" since the numbers are now correct. And, true, it would be matching numbers but it still is not an original engine car, it is just a clone.

Matching numbers may or may not be an original engine car. But you could have a situation where an original engine car is not matching numbers. What? How? Say the owner had the engine rebuilt and in the process it was decked so the numbers on the stamp pad was removed. It now has the correct casting number and casting date but the numbers that identify the engine usage and the VIN derivative are missing. But it is still the original engine.

What is one to do? Two options: 1) only deal in cars that have a documented history or 2) forget the numbers matching nonsense and buy the car you like and drive it.

Tom73 said:
What is one to do? Two options: 1) only deal in cars that have a documented history or 2) forget the numbers matching nonsense and buy the car you like and drive it.

Right on Tom:upthumbs! To be perfectly honest, if I had it to do all over again I would have gone for option 2.

- Eric
I think the numbers game is pretty funny, do you realize how many people buy these overpriced supposed original cars.
Even a nice paper trail means nothing when you can get full points on a restamp.

My god if you can counterfit money, what makes anyone think you can't do it to a buildsheet? A whole hell of a lot more profit, and much easier to pass.
Look at how many L88's there seem to be, or anything with a big block.
Of course it's not just the vette's. I read about a Japanese buinessman that bought some rare piece and while at the same companies museum found what he paid millions for sitting there with his chassie number.

It's getting hard to even believe in one owner cars. You don't know what may have happened.

God bless the true original's out there. But there are a lot fewer than most believe.

Drive'em , enjoy'em, if they break fix'em, most of all enjoy'em

How's that for my 2 cents worth ?


2 More Cents Worth!

When I was looking to re-enter the Corvette ownership after many years, I started to research matching numbers. I found a 1961 with a replaced engine. I had two different individuals tell me if I could locate the correct block (casting number) and casting date, they could restamp the block pad. I passed on this car because of a rusted frame, and was very glad I did. A few months later I purchased a matching number 1961 270HP second owner car for the same price. I beleive you must research the seller as well as the car. Late last summer I was lucky enough to purchase a matching number 1965 with the base 250HP engine. I feel the value of the 250HP will increase as there seems to be a decrease in the amount of 250HP and increase in the 396CI 425HP bigblock on the road.
You can search for a block with the right casting number and a date close to your car's build date but not after, that would be acceptable. Then deck the block and have one of these services add the correct machining (broach) marks and stamp the pad with the correct numbers. A real good NCRS judge will be able to detect it sometimes. More often the car gets the benifit of the doubt.

There is an ethics question here. To have a block restamped for show purposes is a common practice an is considered a "restoration block." To not tell a prospective buyer that the block is not original or represent it as original is fraud by deception and could land you in deep do do. There have been many cases of manufactured numbers on the higher dollar cars like the '67 435hp cars. Did you know that it is widely believed that there are more '67 435s that have been judged Top Flight than were ever built? Shows you that there are some good artists out there. Casting numbers being ground off and refabricated with JB Weld and other methods show up all the time.

Imagine working on your recently purchased high dollar big block car getting it ready for show and you break off one of your block casting numbers and find it isn't iron!!

But back to your question. Some poeple have been lucky and after searching the prior owners history have found the original engine or other pieces in a past owners garage. It has happened but not often. The chance of finding your engine at a swap meet or elswhere has to be up there with winning the lottery.

I believe that there is only one correct engine for any Corvette and that is the one installed during assembly. I would never put a restamp in my '59. However I would install a real Corvette engine that was born with the right numbers or even that '61 270 hp I have in the garage. At least it would be a real Corvette evgine that is of the proper specs. In other words I'll run what I want in my '59 that has been missing it's original block for over 30 years. If I want to get in the show game I'll buy a documented original complete car, restored or not, and go from there.


Corvette Forums

Not a member of the Corvette Action Center?  Join now!  It's free!

Help support the Corvette Action Center!

Supporting Vendors


MacMulkin Chevrolet - The Second Largest Corvette Dealer in the Country!

Advertise with the Corvette Action Center!

Double Your Chances!

Our Partners

Top Bottom