For a 292, the frequency may be as low as 250 Hz. If yes, the only destructive orders you will reach at that speed are the 3rd, 6th and 9th (the 2-1/2 is bad, but it's at 6,000):
3rd 5,000 RPM
6th 2,500
9th 1,667
This means that 4,500 is safe, and you can cruise at any speed between (slightly above) 1,667 and (slightly below) 2,500, or between (slightly above) 2,500 and 4,500.
