Basic Magnum question: Safe maximum RPM on stock internals?

Well, I have been driving my Dart all over the place and the 5.9L Magnum 300 crate motor is running like dream.

How high can you safely rev the stock rotating assembly? Where do the stock motors tend to reach their hp/torque peak?

I have a 5700 RPM governor in the rebuilt 904 but I haven't come anywhere near that RPM yet.