Ask any performance shop if you should run stock rubber valve stems at high speed.
And just because some redneck actually did it and nothing happened doesn't mean you SHOULD do it. :shrug:
Easy there, hot rod! I was just joking that his priority should be looking into a laser jammer to keep from going to jail. :-D
I know when I get the itch to go 150+ mph on public roads the last thing I'm thinking about is valve stems, lol