Topic: What Constitutes 'Matching Numbers'?
in Forum: C3 General Discussion
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So if a C3 has original engine block, transmission and differential, is it technically matching numbers? Or are there other key components that MUST be original for a Vette to be "matching numbers"? How difficult is it to track down say a correct date coded differential for a '71 LS5? What would it cost?


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Former Member
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COLUMBUS, MS - USA
Joined: 1/11/2004
Posts: 331
Vette(s): 1972 Coupe; 350 4-speed with GM sidepipes;
Classic White/Saddle
HUGE QUESTION! ! ! Man, I'm looking forward to the responses this one draws.
To quote "Corvette By The Numbers" author Alan Covin:
" 'Numbers matching' simply means a car which not only appears in original factory condition, but in which ALL pertinent identification numbers, as well as ALL casting numbers and dates, are correct for that specific model and pre-date the final assembly date of the car. It is important to also make the distinction that a car is only original once, PERIOD."
So, in its strictest interpretation (which is all I intend to address), "Matching Numbers" means that EVERY single dated component of the car carries date-stamps that generally precede the vehicle assembly date by no more than 4 to 8 weeks. And by "ALL" we're talking the block (including the crank, connecting rods, cam), intake manifold, exhaust manifold, water pump, distributor, generators and alternators, starter, bell housing, gear box, rear chunk. But it doesn't stop there. It also includes your A/C compressor and all the glass (including the mirrors). Shoot, it even includes the WHEELS!!! All of this stuff has production markings on it to identify what it is and WHEN it was made.
Given the fact that there are parts houses out there (who shall all remain nameless) that will help you build a show car by taking a correct casting and either stamping or restamping the date, I fear the whole "Matching Numbers" thing has become dangerously diluted with "counterfeit" parts.
Just because an engine block has the correct casting number doesn't make it the correct block for that particular car. And that single casting number is only the beginning of a long road to that "numbers matching promised land." Check the dates carefully, research it thoroughly, do your homework. KNOW what you are buying.
I spent many moons studying about this stuff before I went seriously shopping for my Vette. When the dust cleared, I had only paid for what I got - but I got everything that I paid for. A square deal.
I'm anxious to hear how others weigh in on this question.
John

To quote "Corvette By The Numbers" author Alan Covin:
" 'Numbers matching' simply means a car which not only appears in original factory condition, but in which ALL pertinent identification numbers, as well as ALL casting numbers and dates, are correct for that specific model and pre-date the final assembly date of the car. It is important to also make the distinction that a car is only original once, PERIOD."
So, in its strictest interpretation (which is all I intend to address), "Matching Numbers" means that EVERY single dated component of the car carries date-stamps that generally precede the vehicle assembly date by no more than 4 to 8 weeks. And by "ALL" we're talking the block (including the crank, connecting rods, cam), intake manifold, exhaust manifold, water pump, distributor, generators and alternators, starter, bell housing, gear box, rear chunk. But it doesn't stop there. It also includes your A/C compressor and all the glass (including the mirrors). Shoot, it even includes the WHEELS!!! All of this stuff has production markings on it to identify what it is and WHEN it was made.
Given the fact that there are parts houses out there (who shall all remain nameless) that will help you build a show car by taking a correct casting and either stamping or restamping the date, I fear the whole "Matching Numbers" thing has become dangerously diluted with "counterfeit" parts.



Just because an engine block has the correct casting number doesn't make it the correct block for that particular car. And that single casting number is only the beginning of a long road to that "numbers matching promised land." Check the dates carefully, research it thoroughly, do your homework. KNOW what you are buying.
I spent many moons studying about this stuff before I went seriously shopping for my Vette. When the dust cleared, I had only paid for what I got - but I got everything that I paid for. A square deal.


I'm anxious to hear how others weigh in on this question.
John
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Joined: 8/3/2003
Posts: 46
Vette(s): 1971 coupe Warbonnet yellow/black vinyl. 350 automatic
The real-world interpretation of "numbers matching" is essentially all over the map. It ranges from engine block stamp pad matches VIN ONLY to, as the Lumberjack said, EVERY component that has numbers has the RIGHT numbers. NCRS allows a six month pre-build date window for most components.
One very prominent Corvette dealer only goes so far as to vouch for the block stamp on "numbers matching" cars they offer. Kinda of a joke for such "Pros".
So you are on your own when checking out a numbers matching car. One must study the heck out of the reference books prior to inspection. It is a matter of personal preference as to the extent of match desired.
There is no universally accepted definition.
I don't know about the availability of the differential you may need, but I would allow for the six months window mentioned above. I have a very original '71, and most stuff is within eight weeks, but some items are out six months-the shocks I think are one. Some particular parts are VERY difficult to find original and correctly dated. Joining NCRS is a good move if you are into originality, even if you don't plan to build a show car.
One very prominent Corvette dealer only goes so far as to vouch for the block stamp on "numbers matching" cars they offer. Kinda of a joke for such "Pros".
So you are on your own when checking out a numbers matching car. One must study the heck out of the reference books prior to inspection. It is a matter of personal preference as to the extent of match desired.
There is no universally accepted definition.
I don't know about the availability of the differential you may need, but I would allow for the six months window mentioned above. I have a very original '71, and most stuff is within eight weeks, but some items are out six months-the shocks I think are one. Some particular parts are VERY difficult to find original and correctly dated. Joining NCRS is a good move if you are into originality, even if you don't plan to build a show car.
in Forum: C3 General Discussion
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