All our amplifiers since the fP6400 are “burst rated”. The description of the 12dB Lab burst below correctly describes the signal we use for testing.

The 12dB burst has an average to peak ratio of 1/8, meaning that the amplifier can produce bursts 8 times higher in power than what it can deliver continuously. The 1/8 ratio is the farthest we go when rating amplifiers.
Some of our products may have a smaller difference between burst and continuous output power capabilities.

The C series behaves in the same way as the IPD.

So, to sum this up; An amplifier rated at 8000W will deliver (at least) 1000W continuously.