[PurelyGTO68]

Originally Posted by Bigd400

...

Also are body panels date coded?

Most all the panels used to make up the body are stamped with what appears to be a code denoting the week it was formed. These usually take the form of a 3 character code (single letter followed by a 2 digit number). Some panels have a 4 digit code (2 letters with a 2 digit number). Not sure what the letter code represents....perhaps the stamping or die station? The 2 digit number appears to be the week of the year that part was stamped. My car body was assembled during the 21th week of the year. All panels used to make up the body have a 17, 18 or 19 stamp.

Sometimes there is another 4 or 5 digit number stamped in the part and that appears to be a part number of some kind. I saw a thread a while back where someone posted photos of the stamp marks found in rocker panels of earlier cars carried a L or R designation for Left and Right but I didn't see that on any panels from my 1968 car. Maybe they stopped using the L and R by that time???

The bolt on panels from the final assembly plant appear to have a different type of date code. I found stamps on both front fenders. The format might be first character is month, second character is unknown (stamp station or shift?), 3rd and 4th character is day of month and last character is unknown.

The stamp marks for my quarter panels is found near the trunk weatherstrip channel....about 4-6 inches down from the upper corner of the decklid. I didn't discover most of the stampings until after the car was media blasted and epoxy primed. Then many of the stampings were clearly visible.

Here are some photos of my 68....hope some of these help.

[Bigd400]

Originally Posted by PurelyGTO68

Most all the panels used to make up the body are stamped with what appears to be a code denoting the week it was formed. These usually take the form of a 3 character code (single letter followed by a 2 digit number). Some panels have a 4 digit code (2 letters with a 2 digit number). Not sure what the letter code represents....perhaps the stamping or die station? The 2 digit number appears to be the week of the year that part was stamped. My car body was assembled during the 21th week of the year. All panels used to make up the body have a 17, 18 or 19 stamp.

Sometimes there is another 4 or 5 digit number stamped in the part and that appears to be a part number of some kind. I saw a thread a while back where someone posted photos of the stamp marks found in rocker panels of earlier cars carried a L or R designation for Left and Right but I didn't see that on any panels from my 1968 car. Maybe they stopped using the L and R by that time???

The bolt on panels from the final assembly plant appear to have a different type of date code. I found stamps on both front fenders. The format might be first character is month, second character is unknown (stamp station or shift?), 3rd and 4th character is day of month and last character is unknown.

The stamp marks for my quarter panels is found near the trunk weatherstrip channel....about 4-6 inches down from the upper corner of the decklid. I didn't discover most of the stampings until after the car was media blasted and epoxy primed. Then many of the stampings were clearly visible.

Here are some photos of my 68....hope some of these help.

Yes thanks, that does help make some sense of it! So all the panels would have been made in 1969 or what ever year the car is made? They would of just stamped so many pieces and what they had left would just be spare parts for that model?

The car has had some body work done in the early 70's and I was just trying to figure out what has been replaced..

[Formulajones]

Originally Posted by Baron Von Zeppelin

Hey Jones , was your car built in Baltimore Plant ?

We have never been able to source a build sheet from any 69 Baltimore A-Body cars.
Yours would be great to see , if that is the case.
Thanks

Yes, it's an early Sept 68 build from the Baltimore plant, blacked out tail panel etc... Build sheet was on top of the gas tank. If I remember, I believe we left it there (original tank stashed away) couldn't remove without destroying.

[PurelyGTO68]

Originally Posted by Bigd400

Yes thanks, that does help make some sense of it! So all the panels would have been made in 1969 or what ever year the car is made? They would of just stamped so many pieces and what they had left would just be spare parts for that model?

The car has had some body work done in the early 70's and I was just trying to figure out what has been replaced..

I expect body panels were stamped on a regular basis to keep up with demand for any given production year so the week date should precede the date on the cowl tag. The cowl tag has a code that identifies the week that Fisher Body began building the body shell and associated components. So for example....a 1969 model year car body that begins assembly in the first week of Dec 1968 should have body panels stamped anywhere in the 44-46 week range. Similarly a car that begins assembly on the 20th week would expect to have panels stamped several weeks earlier (17-19th weeks). Of course exceptions do exist so it helps to keep that in mind.

It is worth noting the body is built, painted and trimmed at the body plant prior to mobilizing it to final assembly plant where it gets mounted to the engine/chassis and then fitted with the front clip, bumpers and misc pieces. Prior to the GMAD consolidation, the body plant was Fisher Body and a separate revenue center for all GM divisions. By 1970 or so, Fisher Body was phased out and General Motors Assembly Division had taken its place so it's a little fuzzy around that time as to what operations took place where.

It helps to understand how these cars were assembled in order to restore them in a correct fashion. Generally speaking, the basic process of building a car remained the same no matter who built the body (Fisher or GMAD).....the body plant built the shell with the stamped panels necessary for whatever body style they were building. The cowl tag contained the necessary info for most all items the body plant was responsible for. Things like model, body style, color, upholstery color and style, glass, trim moldings etc. The body plant provided a fully painted and trimmed car from the firewall back less the front seats, front carpet and dash components (forward wiring harness, steering column, instrument cluster, HVAC assembly etc).

Engines and transmissions were built at a single factory and shipped to each final assembly plant where they were set in a chassis just prior to the body arriving from the body plant (which was nearby.....like next door to the final assembly plant). Once the rolling chassis was ready, the body was attached and then the front clip was installed along with the dash components, steering column, forward carpet, front seats, bumpers, fuel tank etc.

Some variations exist depending on the model but the general process is about the same. This means the body, doors and deck lid was built, painted and assembled at a different location from where the fenders, hood and endura noses were painted. This likely explains why the stamping codes are different on those parts that were made, painted and bolted on by the Final Assembly Plant compared to the parts made at the Body Plant.

Several sub assemblies were made by vendor suppliers off site and shipped to the Final Assembly Plants such as frames, steering boxes and pumps etc. Its all very fascinating.

Sounds like an interesting car you have there and should make for an interesting project.

[Formulajones]

Originally Posted by PurelyGTO68

I expect body panels were stamped on a regular basis to keep up with demand for any given production year so the week date should precede the date on the cowl tag. The cowl tag has a code that identifies the week that Fisher Body began building the body shell and associated components. So for example....a 1969 model year car body that begins assembly in the first week of Dec 1968 should have body panels stamped anywhere in the 44-46 week range. Similarly a car that begins assembly on the 20th week would expect to have panels stamped several weeks earlier (17-19th weeks). Of course exceptions do exist so it helps to keep that in mind.

It's model and plant specific but I find most of the time the sheet metal date stamps are very close to build dates.
All the sheet metal on my fathers GTO from Baltimore is within a week of it's production date. My 69 Z/28 is a Norwood 12D 68 build and every piece on the car is stamped 50 or 51 which is just a week prior or even a few days before the cars scheduled build date. My Formula is from Van Nuys and also very close.

[PurelyGTO68]

Originally Posted by Formulajones

It's model and plant specific but I find most of the time the sheet metal date stamps are very close to build dates.
All the sheet metal on my fathers GTO from Baltimore is within a week of it's production date. My 69 Z/28 is a Norwood 12D 68 build and every piece on the car is stamped 50 or 51 which is just a week prior or even a few days before the cars scheduled build date. My Formula is from Van Nuys and also very close.

That makes sense. F body cars all came from just 2 or 3 plants if I remember correctly so I would expect the panel stamps to be very close to the build date. Probably the same for the Pontiac plant since they only made Pontiac models.....is that correct?

I think other plants such as Arlington may have produced other GM makes along with Pontiacs so those could have panels made several weeks earlier. It might be a possible reason for the other part number type of stamp that is seen on some panels since those appear to be specific to Pontiac. I see a lot of numbers starting with "2" and that was the division number for Pontiac so maybe there is some room for that theory to work?

Sent from my SM-G930V using Tapatalk

[Formulajones]

Correct, for F-bodies we had Norwood and Van Nuys. However Van Nuys also built full size cars I believe. Norwood was strictly F-body.

Arlington for sure produced Chevy's because that's where my Chevelle was built. I'm fairly certain Baltimore also built A-body Chevy's along with Pontiac.


One reason I'm sure of why sheet metal date code stamps are so close to the build date on F-bodies is because Cincinnati also had a Fisher Body plant close by as well as part of the plant being connected to Fisher. My Grandfather retired from there. Van Nuys was also similar and consolidated a lot of the Fisher and GM assembly processes in one plant.

[Bigd400]

Originally Posted by PurelyGTO68

I expect body panels were stamped on a regular basis to keep up with demand for any given production year so the week date should precede the date on the cowl tag. The cowl tag has a code that identifies the week that Fisher Body began building the body shell and associated components. So for example....a 1969 model year car body that begins assembly in the first week of Dec 1968 should have body panels stamped anywhere in the 44-46 week range. Similarly a car that begins assembly on the 20th week would expect to have panels stamped several weeks earlier (17-19th weeks). Of course exceptions do exist so it helps to keep that in mind.

It is worth noting the body is built, painted and trimmed at the body plant prior to mobilizing it to final assembly plant where it gets mounted to the engine/chassis and then fitted with the front clip, bumpers and misc pieces. Prior to the GMAD consolidation, the body plant was Fisher Body and a separate revenue center for all GM divisions. By 1970 or so, Fisher Body was phased out and General Motors Assembly Division had taken its place so it's a little fuzzy around that time as to what operations took place where.

It helps to understand how these cars were assembled in order to restore them in a correct fashion. Generally speaking, the basic process of building a car remained the same no matter who built the body (Fisher or GMAD).....the body plant built the shell with the stamped panels necessary for whatever body style they were building. The cowl tag contained the necessary info for most all items the body plant was responsible for. Things like model, body style, color, upholstery color and style, glass, trim moldings etc. The body plant provided a fully painted and trimmed car from the firewall back less the front seats, front carpet and dash components (forward wiring harness, steering column, instrument cluster, HVAC assembly etc).

Engines and transmissions were built at a single factory and shipped to each final assembly plant where they were set in a chassis just prior to the body arriving from the body plant (which was nearby.....like next door to the final assembly plant). Once the rolling chassis was ready, the body was attached and then the front clip was installed along with the dash components, steering column, forward carpet, front seats, bumpers, fuel tank etc.

Some variations exist depending on the model but the general process is about the same. This means the body, doors and deck lid was built, painted and assembled at a different location from where the fenders, hood and endura noses were painted. This likely explains why the stamping codes are different on those parts that were made, painted and bolted on by the Final Assembly Plant compared to the parts made at the Body Plant.

Several sub assemblies were made by vendor suppliers off site and shipped to the Final Assembly Plants such as frames, steering boxes and pumps etc. Its all very fascinating.

Sounds like an interesting car you have there and should make for an interesting project.

Thanks for all the info this is really helping put everything together!

Looks like date coding you mention is making sense. I thought I new the history of the car but once it started getting stripped it was apparent I didn't. Appears the passenger side had seen some previous damage. I could tell the rear quarter had been done but looks more was replaced. Once the fender was off the proof was there. Glad they decided to fix it!

[Judas]

Some random bits of info I'll add:

I have a Baltimore car (which is extra cool to me since I was born and raised there) and there was no build sheet to be found. I tore my car down to nothing but a pile of parts and never found one. Obviously its possible that a prior owner (of which my car had several) could have removed them during repairs over the decades.

Oem metal is for sure better than any repop, but they don't always fit or match perfectly like we'd hope. This is probably due to them being stamped out at different plants. My west coast oem quarter does not have exactly the same curvature as the quarter on the car and it gave me a lot of fitment trouble esp near the tailpanel. It is going to require some bondo to make it perfect. Also, I ran into a real oddity with the frame-to-firewall braces I sourced from another GTO of the same year (maybe it was a Lemans?): the welded on nuts for the inner fender-to-brace nuts have different threading. This part came from Arizona. So on one side, I have that sheet metal style coarse threading (like on a wooden lag bolt) and on the other regular SAE coarse threading. This *really confused me when I was trying to put the inner fenders on. I was like "I took this bolt from the other side, yet it doesnt fit this side? Whats going on??"

Be sure to check the lower, inner cowls for rust out. I've read that there was a strike in 68 that lead to 69's having chickenwire cowl vent covers. Whatever the cause, these totally sucked and let in all kinds of leaves and debris. Mine had the chickenwire and both my lower cowls were completely rotted inside and out. Repairing this area is NOT fun. I've heard all A-bodys are susceptible to this but the 69 GTO is particularly notorious for it.

Looks like a great car though. Good luck!

[PurelyGTO68]

According to my neighbor (retired insurance adjuster) and his brother (Fisher Body employee)....no two formed panels are exactly the same. Temperature, friction and die wear are variables that cause variations from one formed part to the next. My neighbor's brother formed panels at one of the Fisher plants and they used the date and number codes as proofing marks and he had to constantly adjust the forming machine during his shift. This could explain why we see clear characters in some pieces and lightly stamped characters in others. These days the machines are computer controlled and they adjust the hydraulic pressure several times a second during each operation so variations between articles are minimized.

Reportedly, some panels had a checking jig and anything that passed would move along to the production line. Those that didn't pass would become service replacement parts or recycled if the tolerances were too great. Most parts would have a proofing mark of some kind and if the mark didn't transfer completely then that part might not make it to the production line. Really depended on the part I am told.

Apparently, the production line wanted the best parts since those guys didn't have very much time to fiddle around. The parts used for service replacements may be less than ideal but the body shop guys would work them to fit the specific car they were repairing so time spent was less of a concern.

If any of this is true...then I suppose it could explain why some NOS panels fit great while others may not be so great. Same would be true for reproduction parts. Also would explain why parts from a donor car is most everyone's first choice.

Sounds reasonable to me...


Sent from my SM-G930V using Tapatalk

[Greg Reid]

Judas, the '68 model is the one that had the chicken wire. My car still wears it proudly...lol

[GTO JONES]

Originally Posted by Greg Reid

Judas, the '68 model is the one that had the chicken wire. My car still wears it proudly...lol

Mine to lol

[Greg Reid]

So, they changed over to the plastic in '70 or when?

[GTO JONES]

I think later in 69 they changed, early builds had chicken wire, from my understanding.

[Greg Reid]

Sounds about right as most '69s I see do not have it. Always been a '68 thing in my mind at least. One of those things that '69 owners like to rag on '68 owners about..like vent windows and the 'ugly' rear bumper...lol

[GTO JONES]

One thing I hit on long time ago was the blacked out tail panel, mine had it and it was built in Baltimore, one (expert) said they didn't do it but I'm the original owner and it came that way. Still gets me lol.

[Bigd400]

Funny the body guys thought it was actually chicken wire and were going to throw it out.

Got the car stripped and blasted, frame is stripped and going in soon as well. Interesting found the vin stamped on the firewall and on the passenger cowl about 6” away from the one on the firewall. They stamp them anywhere else? Is the frame usually stamped aswell?

Got a pile of pictures and a bunch more question for the experts on what’s possibly original or has been replaced. I’ll go through my pictures and post them up later.

First though I need to get all my parts order to get the chassis ready when it get back. What are the things that should be replaced (safety wise) vs keeping things original??

The front to back fuel and brake lines? Shock will be changed but do you go with the original style or something that preforms better? Springs? Who had the best complete front end kit? Still has the original style ball joints is it worth trying to replicate them?

[66beaumont]

Originally Posted by GTO JONES

I think later in 69 they changed, early builds had chicken wire, from my understanding.

My 3rd week April built 69 has the chicken wire

[Greg Reid]

Originally Posted by Bigd400

Is the frame usually stamped aswell?

Right behind of the driver's side wheel arch, on top.

[Judas]

Originally Posted by Greg Reid

Judas, the '68 model is the one that had the chicken wire. My car still wears it proudly...lol

Mines an early 69 (IIRC, it was a Dec/68 build) and it had the chickenwire :/ I've replaced it with 70 plastic vents. I also have the weird 1/2 year short style water pump- another source of confusion at one point.

I used to have the chickenwire in my basement but between it being warped and bent...and it being chickenwire...I tossed it out.