In replacing my evaporator, I pulled the engine side of the suitcase, (grrrrr. nasty job). Pulled the Evap out and cleaned up the firewall a little and presto, crayon markings. I will take pics later and post here, (batteries charging). The numbers were
15/2 I have no idea what they mean of course but if it helps CRG, Im glad to find it. Also found some stamping numbers on the firewall too but need to chalk them for a pic so I can read them. Will post those too later.
Its fun finding new things graemlins/thumbsup.gif

I found the same behind my heater core cover. Maybe even the same numbers you have. See below:


crayon markings (http://hobbystage.net/camaro/media.cgi?site=jonesy&folder=*&group=1&page=*&id=1021153068-000048)

Finally got some pics downloaded of my firewall marks. Exact same as yours Jonesy, almost looks like same handwriting too. Its in slightly different area probably due to my A/C but sure wish we knew what they mean. CRG can have these for future reference.
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http://www.brainerd.net/~knudsen/69RS/UnderHood/fireall%20Marks.JPG http://www.brainerd.net/~knudsen/69RS/UnderHood/firewall%20marks1.JPG http://www.brainerd.net/~knudsen/69RS/UnderHood/firewall%20marks2.JPG

I thought mine was a 151 but now I think it is like yours and is 15/2. Ours cars arent that far apart are they?

Nope, Ive got a 10c Oct 3rd week build date in 68. Wonder if there is a time correlation to these firewall numbers or not. ?

I'll take a wild guess at what the numbers mean. Do your cars have the "P T B" stamps? If they don't, could these be an inspectors mark for (15) items checked on the (/2) second shift? :confused:

They are VanNuys cars, thus no PTB stampings.

If you guys look a little closer, you might notice more stamped charactors below the partial VIN stamp under the heater motor hole.
Mine is stamped something like K M3 or something to that effect. I noticed it a long time ago. There weren't any chalk or crayon marks though. No A/C and a 01C car.

Some cars had VIN's stamped in this location, some didnt. I have simular numbers stamped K 44 or something like that. The stamping is made out in the pic below, just below the hole for the blower motor and below the two dimples. I dont have my VIN stamped here.

Jonesy's looks like a rotation / sequence # for the car as it came down the line.
Not sure on Jim's. Look like it has a different purpose.

I'd guess the 15/2 grease pencil marks are the Fisher Trim Line inspector's punch number/shift marking for final Trim buyoff. Each repairman and inspector carried a custom-made paper punch with either their initials or a number assigned to them to punch off items on the card-stock repair tickets, but the tickets were pulled at the end of the Fisher Trim Shop before the body went up the ramp to Chevrolet. Chevrolet attached their own inspection/repair ticket after the body was scheduled onto their Trim Line.

Additional short number codes stamped into the panel are Fisher Body "run numbers" that were stamped into the panel by inserts in the first-stage draw die at the stamping plant; they indicate which plant stamped it, and the calendar week of the year. graemlins/thumbsup.gif

So in my case, K was the plant and 44 was the week which would be the 44th week of the year. Most of my panels are stamped K 44. The 44th week would be last week of Oct 1968, about 2 weeks before my car was built.

No wonder the A/C systems didn't work well on first gen. Camaros. The heater core pipe runs right in the path of the air coming from the blower. So the air is heated before it goes throught the evaporator. I would wrap some A/C sealer tape around that pipe before putting eveything back together, Click.

thanks pdq never thought of that but with the heater lever on OFF there shouldnt be an flow to keep the heat moving right? Might be some 'conducted' heat thru the copper I suppose but its sure easy to coat it now when I get the parts this week, thanks for the heads up graemlins/thumbsup.gif

No the air isn't heated by the water in the tubes when the A/C is on. That's why A/C cars get the heater shutoff valve, that closes in A/C mode. Probably not the main reason, since you wouldn't pick up a whole lot of heat from two pipes that size that are before the evaporator anyway.

Thats true Mark that shut off is in line there but not in the photo.
I chalked a stamping of 3 numbers above the 15/2 numbers. It is very faint and best I can make out is the numbers appear to be 83H but not all that clear either. Not sure what that would mean? Would H be August? Firewall built then for Oct built car?
Thanks JohnZ for the 15/2 info. its cool to learn about how these all worked.
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Hey everyone

I know this thread is about a month old, but im new and was going through all the threads. Have a car in the shop now that the firewall looked like graffiti once we got into it. C60 and Z22 under where the AC suitcase is, plus D80 above the tunnel and VE3 (from what i can see, hard to tell) partially under the suitcase towards the tunnel. Also had a number (cant remember which, but had nothing to do with color or trim) followed by what i can only describe as an upside down quesion mark right by the cowl tag. Seems they wrote down a lot of the options of the car on the firewall, but found no PBT stamps, and its a norwood car.

Just goes to show theres seems to be no real answer as to what was and wasnt. Has always seemed to be pretty random

dave

Dave welcome to Team Camaro, quick run and take pics of your firewall chalk numbers and then jot down the cowl tag numbers and VIN and tranny and axle numbers too. Post them all in the TAG section here and if you can host your photos of the firewall on the net, you can link them here at TC and share them with us all. We are a curious bunch. Feel free to start a new topic thread of your own if you want too.
Sounds very interesting with all those numbers.
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I found PTB stamp under the suitcase on my Oct 69 Norwood car. No other crayon marks.