Generally, once power peaks, it tends to drop off rather rapidly with increased speed. Unless this peak is a slight bump in the curve like the peak torque on the 790 engine, there would be no point in running it over maybe 5100. The HD big twins, for an example, peak at 5100 or 5200 depending on the version and redline at 5500.

Let's hope there's intelligent life somewhere in space 'cause it's buggar all down here. -- Monte Python