Open Headers and burnt valves?

[Torque Junkie]

This is a tech question that really doesnt fit into any category, so I put it here.

I just got the headers on my truck installed, and I need to drive it 5 miles into town to have the rest of the exhaust system welded, bent and hung.  My question is, is how much validity in the rumors I've heard about running open headers burning the valves?  I talked to a guy earlier tonight and he was saying how the cold air rushing back into the headers after the engine turns off after being hot damages the valves, and that when I drive it that I should stuff rags into the collector as soon as I turn the engine off.  

Is there any truth to that, or should I not be concerned with it for only one 5 mile trip?

Thanks!

-Mike

[Guest Friz]

I've heard that as well, but I've never seen it happen.

I've run open headers on street cars for brief periods like you are going to do, and I've also raced cars with open headers week after week with no burnt valves.

[HiG4s]

As long as they are not shortys I wouldn't be too concerened.

[Charles]

 With headers you'll be fine. It would be a good idea not to rev the engine high and let off the gas. Just drive it nice and easy. My dad put a Buick V6 in a Luv truck and we fired it up with no exhaust manifolds. It sounded and looked so cool. It was just starting to get dark and the blue flames were impressive.

[Bill89]

You won't have any problems with a short trip.  Just like friz I race.  And I use open headers.  

[Pastmaster]

Full-length you should be fine.  I know a couple of people who run them without any trouble for along time.  Shorty's and manifold's-no.  Not enough back-pressure.

[76BBSub]

When you let off the throttle at higher RPMs you create a suction on the exhaust valve during the overlap of valves due to cam timing...this is normal.  If you had shorty headers and the outside air was REALLY cold, and the valves were REALLY hot you could have problem.

That being said, I have driven every vehicle I've put headers on (4 total) without exhaust and never had a problem.  It may backfire a little when you let off the throttle, I'd just keep the RPMs a little lower than normal and avoid just shutting the throttle completely while the truck is still rolling...

BUT, enjoy the sound, wide open headers are awesome!!  And you have an excuse when the cop pulls you over, "I was just on my way to have this hooked up"

Jeff