I have the QTP off-road Y-pipe with dual electric cutouts after the headers and someone told me that running open headers will warp the valves in my heads because the headers let in cold air (I guess when decelerating?) He said that was why race cars always have those flaps at the end of the headers. Is there any truth to this?

 

Not with Longtubes

 

It's not considered an issue with longtubes. By the time air gets up the headers and to the valves it has been heated by the header. I wouldn't even consider it a problem with LT unless it was really rather cold outside. If it worries you, then you can put rags in the collector when you shut it off. It is not a problem while running, even on deceleration AFAIK. I ran open headers for 6 weeks. It was fun for awhile....I plan to get dual cutouts to open header soon now too

 

I have only heard of warped valves and warped heads being caused by running NO headers, or exhaust manifolds. Straight exhaust right out of the head itself. That will warp them to ****.

Don't sweat it. Look how many big drag cars run open headers.

 

run manifolds are you are great. it wouldnt worry about it unless you are running wot in zero degree temps and short headers or so.

 

Ditto . . . never start it up with the heads bare, but open headers are fine. You see this at oval track races all the time.