71 factory numbers

[Gerard Q.]

Thought I'd share a pic of some factory numbers found on my 71 s/b convertible during restoration. This is in the area ahead of the rear deck. I didn't realize factory numbers would be found there. I think I have them figured out.

1. M40 = auto/trans

2. 467 = short hand for 19467 roadster bodystyle

3. A/C = AC

4. UA6 = factory alarm

[Chuck S.]

Re: 71 factory numbers

Yep, you got'em. I compared your markings with those on my 70 coupe. My markings are very similar, except that I have the four speed. From this, I think learned a little more: I conclude that the four corners of the rear compartment were used as "writing space", but no effort was made to put any option code in the same location.

Using your table, my option codes were located at the positions shown written in parentheses. The only possible purposes is that they were trying to keep the A/C on the left side of the deck (reason ?), and the body type (reason ?) on the right side of the deck. UA6 made no difference which side.

1. M40 = auto/trans (A/C)

2. 467 = short hand for 19467 roadster bodystyle (blank)

3. A/C = AC (UA6)

4. UA6 = factory alarm (437)

[Gerard Q.]

Re: 71 factory numbers

That's intersting Chuck. I had not read where this area was used to indicate options. I wonder if it started in 68 or did the C2's also have such as area where the factory line wrote option codes.

[Chuck S.]

Re: 71 factory numbers

I don't think the marking techniques were specific to the model class (C1,C2,C3, etc.), but may have been evolutionary as GM improved production methods.

Over time, as more options were added, no doubt bad experiences led to additional markings to keep line workers informed. While the marking techniques were probably not deliberately specific to the model class, GM may have used the model class change as a time to re-examine production requirements, and at that time there may have been "step" changes in the way they did things markingwise. We are indebted to guys that worked there, like John Hinckley, for helping us understand the markings and other production methods. I recommend a search of the archives...there is a large and invaluable collection of info on chassis/body markings.

It is reasonable to believe that the group of inspectors and supervisors that were working at any given period may have had strong influence in revising or adding markings that their daily work experience indicated as needed. Further, I expect that individual inspectors may also have had slightly different ways of marking the cars, such that some marks could be identified as being made by a certain inspector (placement, characters, etc.). Those marks would be very familiar to workers on his shift, but they would also still be understandable by the next shift.

I would not be surprised if the markings were similar between model classes, but I have seen markings done differently within the same model year...possibly even from one shift to the next as I suggested above. Maybe some owners interested in other model classes can add something here. Some markings made on 72s, for example, are quite "different" from those on say 70s and 71s.

Typically, the bodies were marked in locations to make it clear and convenient for the line workers to assemble the car as specified. On C3s, you will find marks on both front lower foot wells (placed such that the marks were visible with the body elevated). Other marks referencing nearby option features (maybe a wiring harness, mounting clips, or the option itself) are found on the luggage stop bulkhead, rear compartment floor, on the rear of passenger compartment bulkhead, inside fender surfaces (under blackout), exhaust panel, and other locations. It's an adventure to find them all, but I don't recommend letting your curiosity lure you into a body off restoration.