Question about underbody heatshields 1968
 

I have seen the underbody metal heatshields listed for sale for 1968L Corvettes. I have not seen any 1968E. Is that because they did not use them at all at the beginning of the model year? Or were they different and maybe not available anymore?

A heat-insulating blanket made of yellow fiberglass sandwiched between aluminum foil is found above the transmission. It is held in place by clips on the inside of the transmission tunnel fiberglass. On early 1968 cars, a fiber-reinforced aluminum foil batting is used in front of the toe pan. An opaque white plastic shield in front of the toe pan appears in late 1968 production. It is notched on the passenger's side to clear the heater hoses. In addition, a unique triangular shaped metal heat shield, painted semi-gloss black, extends from where the frame rail begins to curve inward to the toe pan on each side in early 1968s. From S/N 9939, another set of heat shields is added. These are rectangular in shape and extend from the toe pan back to the cross brace and from inside the frame to the transmission. This second set of heat shields is described in a Dealer Technical Service Bulletin (TSB) of 22 April 1968 and may appear on earlier cars as a result. A TSB of 17 December 1968 recommends the removal of the triangular heat shield on early 1968 cars and the addition of the rectangular heat shield described above.

Buy the metal ones...ITs nice not to have road debris putting holes and cracks on your fiberglass floor

heat shields
 

I have the heat shields on my 1970. I removed them and painted them then added insulation between them and the body. You dont see them and it adds another layer of heat insulation for good measure. I did have to trim the driver side a bit to not interfere with the long tube headers on my BB

I like this reply, it makes sense. I am wondering how they attach to the body. Screws? I assume if that is the case and there are no existing threaded holes because of date of manufacture I should be able to just create them. Maybe sandwich a bit of insulation in there as well. (per wvleon's suggestion)

Just use an insulation that wont clot or hold water if you get caught in a down pour, hit a puddle, wash the car...etc