Problem with Harland Sharp rockers

Sorry, but something else was going on. My friend ran Harland Sharp rockers for many seasons in a 400 in his Road Runner. It made many passes down the strip, buzzing it to 7500. The engine had a .750 lift Comp Cam roller in it.

Even when it was over-revved when he let a friend drive it down the track once, it banged u p the rockers a bit and bent a few valves, but the motor didn't completely grenade.