Need help with gearbox VIN derivative

[Duke W.]

I've got a Borg-Warner T-50 that I'm trying to decode and need some help. It was supposed to have been removed from a '79 Sunbird (H-special).

The VIN derivative is: 297517918

2 = Pontiac
9 = 1979
7 = plant code
517918 = sequence number

I can't find the plant code. What I have is that and H-specials were built at
Ste. Terese (2), Southgate (C), and Arlington (C) - nothing with a code "7" unless I maybe have Ste. Terese wrong.

The T-50 was also available on Olds X and A bodies, but a list of plants and plant codes that I got from an Olds guy for Omega and Cutlass did not include "7".

Can anyone decode the "7" plant code? It's clearly a seven as all the numbers are stamped very clear.

The other issue that has me confused is the sequence number - 517918. I know Chevrolet sequence numbers start with 100001. Did Pontiacs start with 400001. H-specials were good sellers in the late seventies, but I don't think any division could have sold more than about 250,000.

Any ideas?

Duke

[Joe L.]

Re: Need help with gearbox VIN derivative

Duke-----

I don't have a decoding reference for GM plant codes for 1979, at least, not one that I've been able to find. However, I can tell you this: the vast majority of Sunbirds, if not every Sunbird, being made for the 1979 model year were produced at Lordstown, OH. If there was any other production done elsewhere, it would have been Lansing, MI or Ramos Arizpe, Mexico and I don't think that the latter plant even existed in 1979. I think that non-Lordstown Sunbirds, if any were made that year, were likley limited to convertible models.

I don't think that any Sunbirds were ever produced at St. Therese, Quebec, Southgate, CA, or Arlington, TX. At that time, I think that Southgate (if that plant was even still open at that time) and Arlington were producing full size Chevrolets at that time. I think that St. Therese was doing Celebrity/Pontiac 6000 cars. In any event, the St Therese code has been "2" since, at least, 1979.

[Duke W.]

Re: Need help with gearbox VIN derivative

Thanks for the info. I forgot about Lordstown, but being the owner of a Cosworth Vega I know the Lordstown code - "U". At least that's what it was when it only produced Vegas from '71 to '77, and I assume the plant code remained the same after the end of Vega production.

Duke

[David D.]

Re: 7 is Lordstown, OH *NM* *NM*

[Duke W.]

Yeah, but...

it was "U" during Vega production. Do you know when/why they changed the plant code?

Duke

[Joe L.]

Re: Yeah, but...

Duke-----

I have now confirmed, too, that "7" is Lordstown, OH, as I expected. When it was changed, I don't know. Why it was changed, I don't know, either.

GM plant codes do change from time-to-time, though. Obviously, one reason is that plants close down and their code becomes "available" for use by another plant. That didn't happen in the case of Lordstown, of course, but it's one reason that codes change. The current "possessor" of our hallowed "S" plant code? It's the GM assembly plant at Ramos Arizpe, Mexico. That's where they currently make the Pontiac Aztec.

[David D.]

Re: Yeah, but...

Duke, I don't know exactly when it changed from "U" to "7", but it has been "7" since at least 1981. So, it would have been changed sometime between the end of Vega (or possibly Monza/Starfire, etc) production and 1981. Dave

[John H.]

Re: Yeah, but...

The Lordstown plant code changed from "U" to "7" around 1982-83 when the Hamtramck ("Poletown") plant opened and got the "U" designation.

[Clem Z.]

maybe they did not want anyone to know

where all those rusty vegas came from.

[Duke W.]

Re: Yeah, but...

Based on the 297 prefix on this '79 Sunbird T-50, it must have changed prior to 1980 - maybe it changed with the start of H-special production in 1978, but I still wonder why the Lordstown plant code was changed from "U" to "7".

I guess GM wanted to erase all traces of the Vega. And, Clem, when was the last time you saw a early seventies Audi 100LS - probably a lot longer ago than the last time you saw an early seventies Vega. I always like to use the 100LS as an example. They rusted just as fast, but cost twice as much. ALL early seventies cars were rust buckets. The early Vegas were worse for some very small cost cutting reasons that later bit GM in the butt, but by 1976 the Vega was about as rust resistant as any contemporaneous car. Reminds me that my neighbor's '77 Corvette appears to be developing some significant bird cage rust, but my Cosworth Vega is rust free.

Duke

[Joe L.]

Re: Yeah, but...

Duke-----

Once GM went to the single character assembly plant codes to conform to the "standardized" VIN nomenclature system, the assembly plant codes are, technically, YEAR-SPECIFIC. In other words, to know for absolute-certain what assembly plant a vehicle was built at, you have to take into account the model year and the assembly plant de-code chart for that PARTICULAR model year. Obviously, there is much carryover and the codes are not changed "willy-nilly" every year. But, they DO change from time-to-time.

To provide empirical evidence to confirm John's information about the "U" code being assigned to the Detroit-Hamtramck Plant, my 1989 Cadillac Eldorado "driver", built at Hamtramck, has the "U" assembly plant code.

[Dick W.]

Re: maybe they did not want anyone to know

Clem, you beat me to the punch. I would be ashamed to admit that I had anything to do with the Vega's. (Although the Cosworth was a neat toy..had 2 of them)

[Clem Z.]

vegas were great car with a BBC under the hood. *NM*

[John H.]

Re: maybe they did not want anyone to know

Well, if the customers had parked/stored them the way we shipped them, all the water would have drained out and only the front bumpers would have rusted (see link below)

[mike cobine]

Re: maybe they did not want anyone to know

My '75 had an aluminum front bumper. I think the '74 did also. At least it was the same shape and configuration.

If they used the original battery in storage, they would be ok, but most replacements didn't have the battery vent caps in a place to prevent spillage. And only a little gas in the tank.

They were a good car, and would have been perceived as one if Chevy hadn't listed a first oil change at 7500 miles. But by 7500 miles, the original engine oil had let the iron rings wear to nothing so naturally they used oil like crazy.

Mine was changed at 500 miles, then every 3500 after, and used about half a quart at 50,000 miles.

The Vega that was nuts with the Cosworth. A friend had one, $6500, and a standard Vega with a header was faster. And a '75 Corvette was based at $6500 for the convertible and $6800 for the coupe. So why buy a black Vega?