Interesting early C3 frame stamping.

[Warren F.]

While under my '71 LS-6 coupe, cleaning and inspecting the undercarriage. I saw a stamping on the frame gussets ( the triangular or cross brace) that have the metal lines running along the edge or perimeter of this brace on each side.

The stamping is a -10 with almost a full circle around it. The circle is open at the 9 o'clock position. Has anyone noticed this. The stamping is the same on both of these braces.

[Joe L.]

Re: Interesting early C3 frame stamping.

Warren-----

This is a VERY common stamping on Corvette frames. However, I don't know and have never been able to determine what the significance of it is. The "-10" is the figure always seen, so it's not as if this represents some sort of "measurement".

[Greg L.]

Re: Interesting early C3 frame stamping.

Warren, I also noticed this marking on the top of the rear main welded crossmember and the transmission crossmember...

[Kent K.]

Re: Interesting early C3 frame stamping.

Warren, Joe & Greg----
Steve Koss mentioned to me one time while restoring my '54 chassis that those marks are identifications of the welder who performed the job. Sort of a signature for quality control. Now I don't know that for sure and I whould hesitate to claim it's true but ... If someone else knows the facts, please let us all know.
You will find similar markings on '54, '67 and '71 for certain. I suspect they are to be found on all steel frames from GM.
Kent #6201

[Eric F.]

Re: Interesting early C3 frame stamping.

I just completed restoring the frame on my 75 and I found the number 20 inside a circle located on the bottom of welded rear crossmember.

It's interesting that the number varies as does the location. I would think the location would be the same if it was a quality control designator. Otherwise how would one know where to look for the marking in the event of a quality problem.