is it a good idea to wrap headers with insulating stuff? i have painted headers and an open element air filter.

 

Check your papers to the headers. I know on most of them I've seen wrapping will void the warranty totally. I've also heard about people wrapping headers and it holds in heat and will eventually crack the metal... I've even heard of horror stories of a guy collapsing a collector and some tubes on a freeway ramp after 500 miles he just bought the headers.... he put wrapping on them from the start.

I wouldn't do it. If you're that worried about reducing heat have them jet hot coated....

 

Get them coated. Do a search about this.

 

Getting them coated is the best way to go.