In the first post of the thread unit_399 posted.
2000w input, this is back in the days when amplifiers were rated by input power.
It shows output for SSB 1KW. drive power is 100 watts
AM/FM is 500 watts with 25 watts drive.
Manufacture specs.
The video is using 200 watts drive.
Sure you can drive the crap out of the tube and get more on the meter, with splatter included as a by product of over driving the tube.
With that said they are not that bad of an amplifier if not abused. I would not advise using it on the ham bands.
Light weight PS, just like the Heath kit SB220 series designed for SSB and will barely work AM as long as HV is reduced and less drive.
The HV PS and tank circuits make the amplifier.
With new tubes, HV PS filter caps replaced and input voltage on 220VAC( if the TR has a tap for that input voltage) you can expect 1200 watts PEP on a TRUE PEP reading watt meter not some sampling circuit type meter. This is using 100 watts of input power. 800 watts avg.
Do not forget the tuned input needs to be added.