Running LS engine on just open manifolds

[LS-K]

I'm at the end point for my truck's swap, but I have to drive about 15 miles into Tucson to have my exhaust done from scratch. My engine still has its original CTS-V manifolds.

I had a friend tell me that I ought to stray away from driving that distance on open manifolds since the valves run the risk of "cooling off too quick". He said that may cause the some kind of un-even re-seating of valves or even bend a valve since they wont cool off steadily like they would if I had a full and complete exhaust.

Any help in dispelling this claim would help. It sounded a bit whacky to me but hey what the hell...I figured why not run this through some folks like yourselves who have seen all kinds of things with these trucks and engines.

Thanks in advance,
Eric