68,69,70 Front Bumper Part Interchangeability
 

The parts that support the front bumper - the frame extension bracket, the front removeable crossmember, and the front bumper bracket - does anyone know what the differences are?

I have been taking bumper parts from my 70 and installing them on a new "69" frame I bought years ago from GM Parts. When I went to install the 70 frame extension bracket (this bracket bolts onto the very first beginning part of the frame), it would not fit - the bolt holes did not line up. Parts catelogs show that the 69 and 70 have the same extention bracket, but the 68 is different. I now think my 69 frame is a 68. If I buy 68 extention brackets, will my 70 removeable crossmember and 70 bumper bracket fit? (Pretty specialized question, but hopefully someone knows.) What's the difference between 68,69 and 70 for these parts? Thanks

68/70,
I really don't have an answer for you. I do think though you should first try to determine what year the GM frame actually is. That may help you to know what parts will interchange and what parts won't.
Sorry I can't help!
Regards,
Alan

Does anyone know where the part number is stamped. I've looked over a lot of the frame but haven't seen it. The frame is sitting on jack stands and has an BB engine/bellhousing/transmission on it so there's some of the underneath of the frame I can't see easily.

Tonight I plan on removing the frame extentions from my 68 (groan) and see if they will fit, my now, mystery frame.

I can tell you there are differences in the main bumper.....my bumper doesnt have a built in 'L' bracket thats used to mount the front grill mounting hardware.

I removed the a passenger side front frame extension from my 68. It's part 3914258 (See 1968 AIM Drawing UPC 14 A2). I went to install it on what should be a 1969 frame, and it didn't fit. I've also tried to install the same part from my 1970. It's part 3958798 (See 1970 AIM Drawing UPC 14 A2). It also did not fit my "1969" frame. According to the Corvette vendor books, the 1970 frame extension should fit on 1969to 1972 C3's.

Question: Could someone who has a 1969 AIM, please look up the number that is shown for the frame extension bracket? Thanks

(The part number for the passenger's side will end in an even integer, the driver's side part will be an odd integer I think.)

I understood from you first post that the frame was bought over the counter, is that so? No chance of a stamp anywhere? Just hoping!!!
Regards,
Alan

Yes, bought over the counter in 1979. Been lugging this frame around with me ever since. The part number would have been on the original paper work, but I've since of course lost it. Got some lifted eyebrows when I ordered it. Not too many non-business individuals order a new frame.

Like many new NOS parts, it does have a defect. At the end of the frame where the long tapered rear bumper mount bracket bolts to, the frame metal has a slight warped sidewall. Doesn't seem to bother any alighnment, just seems to be cosmetic. That's probably why the frame was never used in production and assigned to parts inventory.

Once again (see above message) could someone look up the frame extention part number in an 1969 AIM. Thansk