This is a pretty odd one, my 69 had an option that apparently only offered in 1969. Originally had underbody insulation installed. This insulation was fairly stiff fiberglass covered with foil, very similar to the stuff that is used in household heating and airconditioning systems. There are a number of underbody clips that hold the insulation in place, the clips are the same type that holds the transmission tunnel insulation is held in place with. The section directly under the foot wells is covered by a piece of sheet metal that runs from the bottom of the wheel well to the transmission crossmember.
The problem is that I can't find any reference of how the stuff is supposed to fit. There is one page in the AIM that shows the insulation, but it is impossible to really tell how it fits. It is obivous that the insulation doesn't go much past of the transmission crossmember because the back clips end there.
It also seems obivous that the narrow end of the insulation goes up a little way behind the plastic shields behind the front wheels. Apparently there were some clips that were located there (mine have dissappeared and there are only some rivet holes)
There are some wierd cutouts in the insulation that I can find no obivous reason for other than for the metal brackets that hold the sheet metal shield that covers the bottom of the foot wells.
Here are some pictures of the insulation, if anyone has or had this on their car please let me know how it is supposed to go!
Here is the foil side!

Here is the fiberglass side!

 

Steve, is that new insulation or NOS? I can't imagine it being original as it's far to clean. Have you removed the original insulation or was it long gone? If the stuff in the pictures is new or NOS, was there no instructions for installation?

I've never heard of an underbody insulation RPO or dealer installed option. That doesn't mean it didn't exist- I've just never head of it. Was it on every 69?

Given the material it appears to be made of, I would be very surprised indeed if this was intended to be installed underbody. Undercarpet, maybe or even underhood but underbody, it wouldn't last very long; too easily soaked and/or torn if not in a protected location.

The sheetmetal shield at the front end of each side of the tranny tunnel (heat shields) are supposedly to help keep heat off of your feet. I've never seen insulation behind one; just an air space. If the insulation wraps into the firewall area behind the front wheel, it might be protected enough to survive. but the heat shields get soaked if driving in the rain, so any insulation behind them would be soaked and would retain water, rusting the heat shield out in very short order, I would think.

Hopefully someone can answer your question better; I'm curious now too!!

 

I know a LITTLE bit. Yes, certain 69's had the insulation. My 69....#27963 did not, as it was missing the extra 17 or so clips to retain it. Anyhow, the mats go under the metal shields and "bend" crudely up and over the bellhousing area. Foil goes "outside". It is a crude fit....not custom bent. I bought a set for my car thinking it would be an easy install, and would cut down on cabin heat. When I saw the work involved...installing the clips, etc., I decided against it. The only reference I've ever seen is in the AIM. Corvette Central sells the mats and replacement clips/rivets. Chuck

 

Chuck is right. I did this myself recently while swapping out my close ratio for a wide ratio trans. The narrow end of the insulation goes towards the back of the car. You fold the wide part up and over the bellhousing. There are clips inside the trans tunnel as well to keep it off of the transmission. There should be metal heat shields over the insulation and at the front there should be a plastic splash shield on each side of the car. The insulation extends up to the top of the splash shield, and back to the last clips. This would be so much easier to explain if I had photoshop. :crazy:

AC

 

Thanks guys, I figured that it went up into the bell housing area, but I couldn't figure out how it was supposed to fit, with the already existing transmission insulation. After spending several hours under my car, I think I have it figured out. As Chuck said, it will be a royal pain to get installed and probably isn't worth the effort. A previous owner had removed the old insulation and several of the clips have dissappeared also, but from the rivet holes I can tell where the missing clips go. Now I'm going to just stick it on and start cramming :D I'll take some pictures after I get it installed so you can see how sloppy a job I did.
Thanks guys!