well, finally got the body off the frame thanks to several people here's input. Was doing a degreasing and pressure washing of the frame getting overspray from previous paint jobs and years of caked on grease and road grime. On the passenger side on the outside of the frame I uncovered what appears to be the original frame stamp from the factory along with a couple alignment marks? Is this a fairly common thing to find? Just curious...found it pretty cool!

 

My 79 had the VIN (actually just a portion of the VIN) stamped on the driver side rail on the top.... about where the tranny crossmember is welded....

 

All Vettes of the era had these VIN derivative stamps. There were actually 2 of them on the frame, both on the top side of the drivers side rail... 1 is just forward of the #3 body mount and the other is just rearward of the #4 body mount.

SO YES, if yours is actually on the passenger side ... it is VERY rare.

 

It is on the passenger side and it is stamped upside down about 12" in front of the body mount in front of the rear wheel. And it is stamped on the side, not the top of the frame. The number is 3987883-121. Anyone tell me what the numbers mean? GM part #?
I'd show you a picture but haven't figured that out yet.

 

Here's a picture
http://forums.corvetteforum.com/phot...41/frame_1.JPG

 

I think that is the frame part number. I'm not sure what the second number is. My early 69 frame has:

3949093-61
12.6.68
stenciled on the right side.

My vette has a Dec. 1968 assembly date, but I'm not sure what the date on the frame indicates, body drop, assembly date, or what.

 

Yes its a common thing. The frame part number was "stenciled" in three locations. In addition to the locations you've described, the front end just to the rear of the front wheel well kick up also was stenciled and included a date code. This one usually goes first due to the road dirt.

Your use of "stamp" threw some of the CFers off because there is a frame stamp on the driver's side. The term used to describe the part number is "stencil." Frames were stenciled and shipped upside down and therefore easy to read, thus once installed the part numbers are upside down.

Frame numbers usually indicate whether a frame was for an automatic car or manual transmission. At one point I knew what the "121" referenced but not able to recall. I looked at your photos...looks like an early C3 like pre-rubber bumper model years? What year is it?

Also shims marks where used so that once the rolling chassis got to the body drop point in the assembly line, the workers would know how many shims to use. The factory had an alignment jig that measured the frame. Shim packs were than taped onto the frame...you may have found some masking tape and wondered what it was. Depending on year of vette, workers either used slashesin early years or in later years they used numbers.

Stencil kits are available and restorers work to retain these original marks, both stencils and shim marks.

 

I can "sort of" tell you what the 121 means.

The first number set is the stenciled frame part number. Not sure what year you have, BUT when the frames for that series of cars were first built/designed, it would have been designated -1.

When ANY modifications were made to the frame, the number changed, so you'll find -2, -3, and so on, up till -121 and beyond.

So....there were 121 modifications/changes to the frame up to that point.

These modifications didn't have to be significant.....a hole drilled in an extra place....an extra fuel line clamp, etc.

Chuck

 

It's a march 71 car....wow! 121 modifications?

 

So there were a lot of modifications to the frame between my 69 in Dec. of 1968 and your's in early 1971. 61 to 121.

 

NOT 100% sure about this. Maybe JohnZ could chime in.

I would think that since 63 up frames are basically the same, I would venture a guess that an early 63 frame would be -1. My July 63 car has a frame stencil (repro) of -5. I corrected this on my "edit". I checked.

So....from 63 to 71 is 9 years of production. Some changes are major, like extra gussets, etc. Others are subtle....crossmember changed in 65 for the big block. Some are so minor as to be undetectable. Chuck

 

Interesting, I didn't know what that trailing number meant.
My May 26th 1971 build car has a stencil # 127. It also has a date stencil of 3.12.71

 

Geez, you guys make me jealous, all I have seen on my frame is black tar and rust. Joe

 

where did you find your date stencil? And...was your part # stencil in the same location as mine?

 

Depends on the year, but normally you'll find the stencils on the frame siderail under the passengers door area. Hopefully somebody with more knowledge of 71's will chime in.

They're upside-down. The date is usually white crayon hand marked in front of the part # stencil...also upside down. TOUGH to see.

Whether it's still there is questionable...depends on the frame condition. Chuck