# Online Cowl Tag Decoder



## DataTagDecoder.com (Jul 21, 2021)

Hello all, I have developed an Online Cowl Tag Decoder for all GM cars (except trucks) for the years 1964-1972. I would like to encourage everyone to try it out and give us some feedback. What did we get right? What did we get wrong? Did you find it useful? Our mission is to offer this as a reference and is free of charge to use. We also have some stories and commentary specifically about Cowl Tags that you might find interesting.

Please visit Welcome | datatagdecoder.com and let us know what you think. Thanks much!

DataTagDecoder.com


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## LarryK (Aug 20, 2019)

Hi,
I like the idea of having a place to quickly input data and learn more about the vehicle in question from anywhere with Internet access. For one example, I can see where it would help provide information very quickly about a vehicle being considered for purchase, whether in a used car lot or a farmer's field. It would go a long way to separate the facts from the "story" on the spot too. 

So, I gave it a whirl, comparing it to the information I have on my own car (1970 GTO):
1) The interface is easy to input data, especially if you happen to have a picture of the body tag handy. 
2) The list of upper body colors seems to be incomplete. I didn't see any of the numbers or letters associated with vinyl tops. 
3) My tag didn't list any option codes that I could tell, but did have two 6-digit numbers on the same line as the build date that I haven't a clue as to their meaning - perhaps you know.

I have all my own information documented on an illustrated Excel spreadsheet. PM me if you like, and I can share a copy with you. It might help complete the tables of colors and hopefully provide any other information that currently may be missing. Great start so far.

Best of Luck,
Larry


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## DataTagDecoder.com (Jul 21, 2021)

LarryK said:


> Hi,
> I like the idea of having a place to quickly input data and learn more about the vehicle in question from anywhere with Internet access. For one example, I can see where it would help provide information very quickly about a vehicle being considered for purchase, whether in a used car lot or a farmer's field. It would go a long way to separate the facts from the "story" on the spot too.
> 
> So, I gave it a whirl, comparing it to the information I have on my own car (1970 GTO):
> ...



Hi Larry, 

Thanks for your feedback. Let me hit each point:

I'm glad that you found the interface easy to use. When I was looking into developing this I considered two options; 1) Direct alphanumeric data entry per 'slot' in the tag spaces, and 2) Using drop downs for each possible entry. I chose the latter because it does not depend on where data entry is and I could also control the data being presented and from a technical stance easier to build. which brings be to your second point.

This project will be a work in progress for some time. I can't claim that it will ever be 100% complete or accurate (unless there's someone out there with a pallet of verifiable GM documentation) but I am trying to get as close as I can. Right now I think I'm in the 80-ish percent area and I am shooting for the high 90's. 

Unless I was able to partner with GM or a partner with verifiable access to all GM documentation I don't think I would confidently say that what DTD.Com is presenting can be used for vehicle authentication because a) That source has yet to materialize, b) Cowl Tags are man made and are prone to error to being with, and c) People have been known to swap Cowl Tags. Your point of the site being used as a quick reference is exactly why I developed it. Thank you for seeing that.

Ah yes, the dreaded 6 digit number strings. To Chevrolet's credit the information is much more complete as to what these numbers really mean. It would be helpful if I could get verification from other divisions. Pontiac seems to also have a good handle on these numbers whereas Oldsmobile and Buick the data is a little lacking but the consistent explanation for these strings of numbers is "Internal plant tracking numbers." For Chevrolet I've found the following from Chevellestuff.net:
_"DATA PROCESSING NUMBERS" - "Found on Arlington, Atlanta, Baltimore, Van Nuys, and Kansas City trim tags. These consist of either two 6-digit numbers (Atlanta & Van Nuys), single 5-digit number ( Kansas City), single 4-digit number (Baltimore) or a 3-digit number (Arlington) and represent several data processing numbers found on internal plant paperwork to track the car during assembly. They have nothing to do with any options and are only significant today if paperwork is found for the car and the numbers match up to show that paperwork belongs to that car._​"_Atlanta & Van Nuys:_​_The first 6-digit number can be found in block #24 of the build sheet._​_The second 6-digit number is actually a concatenation of a 2-digit number and a 4-digit number. The first 2 digits are found in block #10 of the build sheet (SCHED NO) and the last 4 digits can be found in block #24 of the build sheet." etc..._​How I will proceed with explanation of those strings will probably be an improvement over time especially if I can get Olds, Pontiac, Buick, or Fisher documents stating exactly what they are. That is one improvement that's on the list along with non-US Cowl Tags (Canada for example) which share most of the same codes but not all.

I know that Pontiac does have some holes in the data from '70-'72 and my research shows that the use of Accessory Codes, or in this case RPO codes, was very inconsistent with some assembly plants putting upwards of 4 on the tag, some have 1, some have none. For example, my 71 Cutlass S has only 1 on it. Yes I would like to see what you have as far as data. If you have any other GM documents to back it up that would be helpful as well. I'll send a DM.

Regards, 

DTD.Com


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## DataTagDecoder.com (Jul 21, 2021)

Hello again, I wanted to announce that over the past week there have been a lot of updates done to DataTagDecoder.Com. Included are:

· Added Assembly Plants for Chevrolet
· Added and Corrected Accessory Codes (64-67) for Pontiac, Oldsmobile, Chevrolet, and Cadillac
· Added Additional Seat Types for Fremont, Ca builds
· Added Explanations for Fremont and Other Assembly Plants Use of Internal Codes (Fremont, etc.) and how and where they are found
· Removed Several Duplicate Records

What’s coming next:

· Adding and Auditing Accessory Codes (64-67) for Buick
· Auditing Assembly Plant Codes for Buick
· Corrections for RPO Codes for All Divisions

Requests:

· If you are aware of any GM related websites not found here, let us know so we can add them to the list. Use this link and use the “Add Link Request” category using the drop-down
· Any other suggestions to improve our data and if you would like to contribute your experience with DataTagDecoder.Com, send us some feedback using this link and selecting the appropriate drop-down

In the meantime, I wanted to thank you all for your feedback. Feel free to comment, correct, and contribute to DataTagDecoder.Com.

DataTagDecoder.com
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