Numbers matching verification

[buckethead]

What numbers do I check and where are they located to verify that my '77 is "numbers matching"? I was told that my car has the original engine but some other non original things I have found make me a little skeptical.
Thanks,

Doug

 

[red70vette]

Numbers matching is a relative term. It usually refers to the VIN number, engine , transmission, and rear end all having the same numbers designating them as original to the car at the time of assembly by GM.

There are numbers on almost every part on the vehicle and for NCRS judging pourposes and some people's opinion they all should match if the car is truly to be truly designated "numbers matching".

The drive train (engine,trans,rear) has the vin derivative on its parts and can be checked for originality versus the vehicle VIN.

If you want to verify the other numbers you will need a NCRS Corvette Specifications guide or some other guide which will tell you what the proper numbers and dates should appear on such items as alternator,distributor,heads,manifolds,radiator,master cylinder etc.,etc., etc. for your vehicle.

The most important thing unless you have a very collectible and rare Corvette is to have a Corvette that you can drive and enjoy regardless of what numbers it has.

It all depends on why you want to know and what you want to do with the information.

 

[buckethead]

Thanks for the info. Not really important to me if the numbers all match , just curious and don't want to give false info if I want to sell it in the future. I agree with you , since it's not a rare model and as long as it's fun to drive it doesn't matter. Right now me and my daughter are both enjoying driving it on the rare sunny days we have been having here in Pa.

 

[DDLS3]

The engine vin number is the easiest to find. It is located on a flat pad on the block between the water pump and the right side cylinder head. Somewhere in the number you should see the last 6 digets of your vin#. The same 6 digets will appear on the rear differential and tranny. You will have to look at bth closely as the location was different dependent on which tranny you have and what model year. I'm not certain where to tell you to look on the rear end, only that it is there.

 

[buckethead]

Dale,

I think I found the pad you described (attached pic) but it is completely smooth. Looks like someone removed the number which is probably not a good indicator that it is the original engine.

 

[buckethead]

let me try again to attach a pic

 

[red70vette]

That is where they should be. It should start with some letters to determine the engine and trans confirufation for example in a 77 the code CLF followed by the last 6 of the VIN # means it came equiped witha L82 Engine 350 /210HP with a turbo Hydra-matic 400. A code of CLD would be the same engine with a 4 speed trans. CLA would be 350/180HP with a turbo 350 trans. All engines have a code on them when manufactured regardless of what vehicle they were installed in or if they were a replacement engine.

If the numbers are missing there is a reason for it. Either it is a none original engine and some one has ground off the numbers to hide the fact or the numbers were accidentally ground off during an engine rebuild where they milled the heads.

Look very closely because those numbers are not the easiest to see.

 

[buckethead]

I cleaned the pad all the way to bare metal, and looked at it up close with a trouble light. Definitely nothing there. Doesn't look like anything was ground off, to smooth and square, had to have been machined. The engine was supposed to have been completely rebuilt.

 

[red70vette]

When the heads are machined the vin numbers are sometimes machined off also. So it is possible that they were removed during a rebuild.

In any case if there are no numbers on the pad to match the Vin on the windshield post then you do not have a numbers matching engine by the most common standard

 

[buckethead]

Thanks for the info Red70. Not a big deal to me but I was curious to know. Just another "mystery car" of which I've had my share in the past

 

[DDLS3]

It is very possible that the block was decked (machined) slightly to assure a flat surface when rebuilt. In this case the numbers, which are small and not deep to start with, ended up on the machine shop floor. Unfortunately with no numbers at all, it will remain a mystery.

 

[Steve Grodin]

When the heads are machined the vin numbers are sometimes machined off also. So it is possible that they were removed during a rebuild.

In any case if there are no numbers on the pad to match the Vin on the windshield post then you do not have a numbers matching engine by the most common standard

The engine code is on the block not the head.