Insulating Wraps By High Output
               Generally, any of the insulating wraps will raise the temp inside the pipe and thus

               speed up the wave activity inside as well. This will cause the wave activity to be

               efficient at a higher rpm than before and raises the powerband (usually narrows it a

               tad, too). If it is jetted and timed complimentarily, there is usually an increase in

               power at the new, somewhat higher peak rpm. Depending on how far down the pipe

               it is wrapped, there is often a corresponding loss of low speed power. You see this

               trick on drag racing vehicles quite frequently because they are trying to build up

               heat in the pipe quickly to match the high rpm that they will be finishing their race

               up with in just seconds. (The other big deal with header wrap for the car guys is

               that any reduction in underhood temp means a cooler and thus denser intake

               mixture.) If it is done correctly, in these situations it can be used as a sort of

               pre-timed, variable exhaust system. But because too much heat wrap can cause

               temps to go too high in extended use situations, you should be very sparing with

               heat wrap until you have verified it to be safe for your length of time of operation.

               Expect to need more main jet and quite likely more mid range fuel as well. You may

               have to limit ignition lead a bit, too. Good luck.