[Whaler]

Start at the source if it isn't too much of a pain...I have heard claims that "jet hot" coating and all the other types in the same vein will reduce cockpit heat and underhood by 200 degrees....
The nascar boys swear by it and only do it to make thier long rides more bearable.
Wrapping headers tends to promote rust and premature rot.

Then after this, go for the thermal barriers as suggested.

A friend of mine used to say he had a buddy who couldn't stand his car as he would cook from the waste down and freeze from the waste up all at once.

I have used the aluminized thermalsleeve (on the brake feeds to the masters from the remotes). Comes in 3 foot lengths. For protecting wires, hoses and lines from heat.
I may also weld on a sheet metal small heat shield on the drivers side header at the same locale.

I only plan on using a good carpet underlay when it comes time to carpet.

Tim