VIN vs. Fisher body # on cowl tag correlation???

[JHS]

I heard from a guy who heard from a guy who..., well, you know, that GM VINs typically are within a 100 digit spread of the Fisher body number on the cowl tag, a possible way to make sure the cowl tag goes with the car. I compared these two numbers on my 67 Z28, 69 Impala SS, 70 Nova SS, 70 Camaro RS/SS and 68 Buick GS 400. Guess what? They all fell well within the 100 digit spread, the farthest off being 35! Has anyone else heard of this or am I just a novice late comer to the hobby? Is this a good way to verify a car's real cowl tag?

[Chevy454]

Nope...!

[JHS]

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Nope...!

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Does this mean it is not a good way to verify or that you have not heard of this before?

[JHS]

Clarification: one only compares the last 3 digits of each set of numbers.

[Chevy454]

Both...never heard it before, and it's not a good method...

[JHS]

I realize it is not a proof positive method but it sure was strange to find that my cars all fell within the parameter indicated, noting that only the last 3 digits of each set of numbers are used. Just wondered if this applied to other members cars?

[Chevy454]

My guess is it's gonna be more of a coincidence thing as the VIN and body # were 2 different entities? Fyi: I grabbed a page of COPO Chevelle #s, and out of the 10 on that page, only 1 of them worked out to be within 100...

[Don_Lightfoot]

I also have not heard of any type of correlation between the two, wish there was. As a matter of interest the difference on my Chevelle is 76 (264 vs 188).

[Verne_Frantz]

JHS,
It gets kind of complicated. If a plant is producing more than one model, such as coupe, convertible, sedan, etc., each body style will have it's own consecutive numbering from Fisher on the cowl tag. The VIN of course is assigned to a chassis in the order of final assembly, no matter which body style winds up on that chassis. There is a correllation of course, but not one where a "difference" in both numbers should be any certain value.
The best way to determine if one number agrees with the other would be to find a known original car built early in production and one late in production. Take the difference in body numbers and the difference in sequential VINs and plot both on the same time line. Then when you find a car with a VIN somewhere within that range, an approximate "expected" body number can be derived. You'd need to plot those production lines for each body style.
Again, it's only an approximation, since the rate of production of one style or another may vary, such as more convertibles in the Spring, etc.
Hope this helps...

Verne

[YENKO DEUCE REGISTRY]

[ QUOTE ]
JHS,
It gets kind of complicated. If a plant is producing more than one model, such as coupe, convertible, sedan, etc., each body style will have it's own consecutive numbering from Fisher on the cowl tag. The VIN of course is assigned to a chassis in the order of final assembly, no matter which body style winds up on that chassis. There is a correllation of course, but not one where a "difference" in both numbers should be any certain value.
The best way to determine if one number agrees with the other would be to find a known original car built early in production and one late in production. Take the difference in body numbers and the difference in sequential VINs and plot both on the same time line. Then when you find a car with a VIN somewhere within that range, an approximate "expected" body number can be derived. You'd need to plot those production lines for each body style.
Again, it's only an approximation, since the rate of production of one style or another may vary, such as more convertibles in the Spring, etc.
Hope this helps...

Verne

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Ditto, well said