[QUOTE=JohnBoyToo;3449650]Back in the hot rod days, they used to wrap the exhaust to keep the heat in the engine bay day in an effort to keep intake temps down as low as possible...
But on my dirt bikes I used to do it to keep from burning myself WHEN I fell
Header wrap is still used on almost all full fendered stock cars to this day, open wheel modified type, not so much. It is also used to help keep down heat near drivers feet (heels) if exhaust passes under car below driver.