I am new to the C3 Corvette world, having owned Mustangs and Cougars for the past 10 years or more and C4 Corvettes before that. In the Ford world, I knew that the head or block would sometimes have the last 6 digits of the VIN stamped on it (our 1968 Cougar has that). Absent that, you'd have to judge numbers matching very loosely according to casting numbers.


Are the Corvette engine blocks supposed to have the last 6 digits of the VIN stamped on them or is there some other correlation between the block stampings and the VIN that determines matching or non-matching?

 

VIN is stamped on engine pad and transmission. If all three are the same then you have "numbers matching".

Does NOT necessarily mean that they are the original parts to the car though.........

 

Vin is stamped on transmission as well is it? Would that just be the last 6 numbers and where exactly on the trans on a 72 please?

 

Since 1960, all Corvette engines have had two sets of numbers, stamped on a pad on the right front of the block, just forward of the head.

One set was an engine ID, made up of a letter for the engine assembly plant, four numbers for the month and day that the engine was assembled, and a two or three letter suffix code, that identified the engine type. The second set of numbers was a VIN derivative. The VIN derivative varies some by year, but it always included the last six digits of the VIN, usually proceeded by additional numbers sometimes identifying the model year, the GM brand (1 is Chevrolet), the model (Corvette is 9), and the assembly plant - "S" for St. Louis or "5" for Bowling Green.

The trans stamping is in the same format as the engine VIN derivative, and was stamped at the same time on the assembly line. Where the trans was stamped, varied by year and trans type. 4 speeds were usually stamped on a machined vertical pad, on the right (passenger) side of the trans case, where it attaches to the tail shaft housing.

The block below is a 66 427, but the basic format is the same or similar for most engines and years.

 

My 71 is stamped on the driver side, just above the pan

 

How does that number correspond to your VIN?

 

120085 is the consecutive unit number for the car. The consecutive unit number becomes part of the complete VIN.

All 1971 Corvettes have the 1 following the plant code (S for St. Louis). The car in the pic was the 20085th 1971 Corvette assembled. Total production was 21801 cars. #20085 was completed near the end of the 1971 production run (21801 - 20085 = 1716 before end of year.)

 

Hi C3,
The term "Numbers Matching" has become miss-used, and so open to interpretation, that many folks don't use it anymore.
As has been explained, in it's narrowest sense the term refers to the stamped information on the engine's 'pad', the stamped information on the transmission, and that information's similarity and appropriateness to the car's VIN information and assembly date.
There are many, many, parts in the engine compartment and through out the car that have part numbers on them, dates or date codes, and configurations that make them appropriate for a specific car.
Some people are only interested in the engine pad while some are interested in the whole car.
Regards,
Alan

 

Well said Alan.

 

Not that I plan on selling any time soon but how do you all see the following affecting my cars value?
The block has been decked so there's no stamp but the trans stamp S510135 matches my VIN.

 

I'm pretty sure the motor in the '73 we're looking at is not the original motor. The number stamped on the right/passenger rear part of the block, just behind the head, reads 4024388C, which doesn't follow a VIN pattern. Could this have been a marine motor?

 

Six of one and half a dozen of the other. At resale time, some potential buyers will want the engine pad stamps; others won't care. A third group won't know about numbers or where to look for them.

 

Also found the number 1295 just below the passenger side head in front.

 

Hi r44,
There are some folks to whom the 'original' engine is very important, but there are others to whom it means very little.
A really nice car is a really nice car whether it has it's original engine or not!
A car with it's original engine is a bit more valuable, but what the rest of the car is has a much larger effect on that value.
Don't worry about it! Your car is what it is!
Regards,
Alan

Do you think the engine is the one that was in the car when it left St.Louis?
Are the rest of the engine components that have part numbers and date
still the original parts?

 

Hi c369,
To go along with gbv62's post here's an example of the stamps on a small block pad.
Regards,
Alan

Upper arrow points to the stamped information that describes where, when, and in what configuration the engine was assembled.
The lower arrow indicates what vehicle the engine was first installed in.

 

There are casting numbers on the block also they unlike the stamped numbers can not be changed. And do tell some info.It seems strange to me that there are so many bbc c2 and c3s that engines have been rebuilt and still have the stamped numbers. Are there stamps available ?

 

The pad in front of the head where the arrows show the stampings is much smaller (maybe 1/3 the size) than the one in the picture and that's where we found the 1295.

 

Post some pics of what you've found.

 

Got my interest, and that isn't always easy to do. I love when mysteries are resolved. Standing bye.
David

 

Hi c369,
The size and shape of the sb stamp pad changed in the later 70s.
Here's an example of each.
Is yours the more square?
Regards,
Alan

This is looking from above with the head removed.