Core Support Numbers, Mystery Solved

For years I have been trying to find out what the hand righten numbers on the core support were meant to be. I first discovered the numbers on my unrestored ’74 Bronco back in 1988. The numbers are located behind the passenger headlight on the face of the core support.
I have seen core support numbers righten on plenty of other Bronco’s and other members have e-mailed photo’s of their numbers. I always thought it had something to do with the build sheet but could never prove it. Build sheets in Bronco’s are found in the interior usually under the floor mat. Only a handful of owners have found them, so I then started studying build sheets that C.B. members have found in their Bronco’s.

For the last 4-5 years I have been trying to find someone with a build sheet AND visible core support numbers. Finally someone has found both, Andy G. (Blue71)has. The pictures are hard to see but it confirmed my Theory. The core support numbers (2883) are the same as the “Rotation Number’’ on the build sheet.

I then started a search on Rotation Numbers on the net.
Here is what I found out ….

The rotation number is the order they come down the line in. They start at 0001 and go to 9999 then start all over again. This is done so a worker can find the car in various parts of the plant without looking at the VIN number. The vin AND rotation numbers are printed on a few papers taped to various parts of a car (front, back, sides and underbody/frame) that tell what options the vehicle takes to help the guys on the line, they are called teletypes. Its an in plant only number and means nothing when it leaves the factory.

These numbers were assigned to all of the vehicle’s built on the line. Once they got to 999 on the forms they just started over again at 001. 001 could have started down the final line (these rotation numbers were the second of two assigned to the car) at 2pm on a Thursday or 9am on a Monday, no way of telling. Just when ever the rotation started over. Same thing with the car that was 564th in the rotation - just a relative place keeper that allowed workers to identify the car and the parts that would go on it rather than use a sequential VIN number that would not be in any order during the build process.

So there you have it, Mystery Solved.

Neat. If these old Broncos could talk.

Ah cool. I've noticed you querying threads every now and then for those numbers. I have the handwritten numbers on my core support, door jam, alas I don't have my build sheet.

Hot damn! Cool info right there


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Yes you are totally correct the engine line would have a teletype machine and the first operator on that line would hang a teletype sheet on the cradle and set the proper engine in it then all the other workers would build to it. The small parts paint would pick the fenders, hood and the grille for the broncos and send them down stairs to be assemble in a sub assemble area. Coming out of the paint trim's first operators would place them on all four sides for the workers, this was because the body would travel down a line then transverse side ways the travel up next line first line would be face forward then backward on the next line. All these teletypes where thin copy paper of the for no better term copies of the master teletype which was a pasteboard thickness that the inspectors used to check content and place their stamp on. This copy was later separated with other documents and archived to be able to go back on check build history and other data. I do not believe they were intend to go with the unit so much as it was just as easy just to throw the carpet over it, or leave its stuffed in the seat cushion. Note look on you glove box door or on the bottom edge of you dash board on the 1973 builds and you will see paint inspector stamp saying paint, month, year and the inspectors name like Jim Venattor who in later years was my; safety; rep.

This story makes me want to pull the rubber mat out of my 69 and see if anything is under there!

I have seen other painted numbers along with what looks like a date on the core support of several Denver Broncos. They don't correspond to VIN sequence and are probably not rotation numbers.

Wyflyer said:

This story makes me want to pull the rubber mat out of my 69 and see if anything is under there!

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Rust and pulp!

Paul

Great detective work, Jack. Super cool!

Thanks Jack and Andy for finally getting the conclusion to the core support numbers...ie Rotation Number! I have noticed the number there for years and figured it was something like that, but not conclusive with anything since it never matched the vin.

Great detective work, Jack! So cool.

Todd Z.

Very cool info! Thanks Jack & Andy for figuring that out. Here's mine before & after I cleaned it.

mtp71174 said:

Note look on you glove box door or on the bottom edge of you dash board on the 1973 builds and you will see paint inspector stamp saying paint, month, year and the inspectors name like Jim Venattor who in later years was my; safety; rep.

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Here is my inspector stamp

Great super sleuthing. I've got a 71 marked 2680.

I've got a '77 marked 2422

Great Find Jack. Finally. Interesting...what color is Andy's Bronco that has the super clear 2883 on its support? Or is that the support. Looks like it has a super grungy coat of paint, yet the white is super clear?? Not saying anything, just curious as I've only ever seen them on regular topcoat, not undercoat or thick paint like pictured.

Viperwolf, I believe you have dealer stock numbers there on that Denver core support

Hey Andrew,

Pic was taken with a flash so all the good old grime showed up in the pic. That's the original paint and rotation number on the core support. The color is original and it's on a 75 Ranger and called Hatteras Green Poly 2614 code (8)

Andy
Blue71

BajaBronco said:

Viperwolf, I believe you have dealer stock numbers there on that Denver core support

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Could be. An interesting thing is I've seen it on 2 Denvers that were originally sold at different dealers.

Very cool. I have always been curious about the "1831" written on my 1968's core support. Recently I folded down the windshield in order to begin removing it. The same "1831" appears on the very top of the dash panel also. Unfortunately, the build sheet is no longer there. Thanks for this great information!

Core support # and matching # on dash

Picture of my core support and dash panel with matching handwritten numbers.