I used a product that I got from Racer Wholesale 1-800-886-RACE or
www.racerwholesale.com It is called Aluminized Heat Barrier and works VERY VERY well. You can also get a spray on glue that is heat resistive and ment to be used with it from them.
The aluminized heat shield "is made of the same high temperature fabric as the header wrap with an aluminized backing. Great for sandwiching between fire wall, floorboards,hoods,fenderwells, or anywhere heat is a problem. Heat barrier is 40" wide X 1/16" thick. 1 Yard $29.99, 5 yards $139.99" quoted from Racer Wholesale catalog.
I used about 3 yards to do the entire rear clip. The outer surface of the car above the headers is cool enought to place your hand on for an extended lenght of time when the car is all warmed up and as hot as it will get.
This stuff is lightweight can be cut with sisors and very effective.
I also used it for the barrier pannel between the engine bay and the drivers compartment.The full 5 yards would do most of the car where you would want to reject heat, footwell, sidepods near water pipes, etc.
I just looked in Jegs 1-800-345-4545
www.jegs.com and they have this stuff also, heatshield, 10 square feet $81.99 jegs part# 893-14001 and glue $12.99,12oz can, sticky stuff adhesive # 900-90-4000