I over revved and pegged the tach. The fan blades curved backwards from the force, and cut into the radiator, causing a baaaaad leak.
If it cames back down, doesn't tick, knock, or have holes in it, it was under the safe limit for that engine...
Maybe next time it won't do it, but this time it did.
Follow the tach recomendations and you are fairly safe. But loose rockers can shuck anytime. A weak valve can drop a head during startup just as easily as during a 8000rpm blast across the salt flats. If the engine doesn't need the revs to make the power, it just beats up the engine needlessly over-revving it. Check your power peak on the dyno, and adjust your shift points to allow the rpm drop into the next g ear to drop you right around peak torque rpm...
Any higher is pointless, regardless of what the tach says.