What about using fiberglass pipe insuation on our exhausts? I figure that TBI EGT's don't get much above 500F, so the pipe's max temperature would have to be less than that because not all of the heat is transferred to the system. Fiberglass insulation is supposed to go up to 1000F, and I know they use it on superheated steam pipes that can be in excess of 450-500F. The pipe insulation wouldn't be nearly as good as the header wraps you can buy, but should be a lot cheaper. I imagine that it would help to protect from the elements (I know pipes corrode from the inside out, but would you rather burn a candle at both ends or only one?) and might help a bit with silencing, since I imagine the pipes must transmit the sound of gases passing through them at least a little bit.
