During the restoration of my frame I have been trying to figure out how this car started out it's life. The trim tag says L48 with a TH400 automatic. That's is what's in the car now. I removed the transmission cross member which was a bolt in as it is supposed to be but the Corvette Restoration Guide says that if you have an automatic trans then there should be no clutch rod bracket on the left side frame rail in front of the #1 body mount. This frame has the manual trans clutch bracket installed in the factory location. Also I found the numbers 2-91 stamped on the transmission cross member but I don't think that it is a month/year stamping because the C3's last year of production was '82, although this could be a replacement cross mount the was a repro in that year? Trying to figure out if this frame is original to the car or if it was changed at some point. I cannot locate any numbers stamped into the frame. The resto guide says that there should be numbers on the left frame rail in front of the #4 body mount location and also in front of the #3 body mount location on the frame kickup. Are these numbers on the top of the frame rails, the side of the frame rails, or on the bottom of the frame rails? Is it possible the numbers were never stamped into the frame?

 

The vin stamp by the #4 mount is on top the frame rail.

 

On a C3, the id numbers on the frame are stamped on the top of the driver side frame rail at or near the #4 body mount bracket.
Sometimes, like mine, the numbers are very hard to see. Especially if there is any rust present. It took me a lot of wire brushing and carefully looking, but they are there.

 

 

Hi T,
I'm curious about the 'trim tag' you mention and the information on it.
My understanding is that the trim tag on the driver's side hinge pillar contained information about when the car was assembled and the exterior and interior colors. Not the drivetrain information.
Knowing the year of your car would help determine what would be a typical configuration for the frame for your car. There was a bit a variation as the years went by.
Here's another picture of one of the locations of the VIN derivative on the frame.
The large machine used to make the impression often left a depression in the frame rail that can be seen and felt with one's fingers. Sometimes even if it can't be seen the location can be felt.
A frame that left St.Louis under a car would have a vin number stamped on it. A service replacement frame would not have one unless it was stamped in some way prior to being installed under a car.
Regards,
Alan

 

The car is a '75. I may have been mistaken about where I got the drive train information. It may have been from the vin number. I'll look when I get home. I will check carefully for those numbers at the #4 location hopefully they will show up with some wire brushing/cleaning of the area.

 

VIN tag, not trim tag. There is no engine code in the trim tag. There is no transmission code in the VIN. You need the engine suffix for tranny ID.

Yes. Both are in the top rail. First position is between #2 and #3 mounts.



Yes if you have a reproduction frame. Highly unlikely if your frame is original.

 

Are there VINs anywhere besides the windsheild post, engine and top of the frame rails? Somewhere easier to read? My windsheild post plate is missing and I want to verify myself before going to the DMV.

 

Hi RD,
There's a partial vin stamp on the transmission case too.
Regards,
Alan

4-speed

 

Original transmissions have the same VIN derivative as the engine. Do you have the original engine? If so, the VIN derivative stamped on the pad can help putting together a full VIN. As far as the frame stamps go, they are also VIN derivatives.

Do you have a vehicle certification sticker on the driver's door? They have complete VINs.

Any original factory paperwork with your car?

Do you have a title? Titles should have complete VINs.

 

Judged a very nice 800 mile 1974 L82 M21 at Kissimmee this weekend with a two-digit grease pencil on the tranny crossmember. It was also common to see this on the rear crossmember. Typically, these markings are the the last two digits of the VIN. See if this reconciles with your VIN sequence.

Hope this helps!

 

I have a title. I'll have to do some more looking.

 

My 68 frame vin# was really lightly stamped by the #4 body mount, it was hard to find. I plan to get the frame powder coated and I am worried it might cover it up? I still haven't found the other stamp by the #2 or 3 body mount. Here is a pic by the #4 mount.