Mayhem on AmRad 40 m. band

[Murphyv310]

I'd not be using batteries! Hence the CCS power for filaments. I can't see how the published specs allow anywhere near those outputs.

Interesting you say that the specs differ from what's been achieved.
Look at the PL509, PL519 and EL519. Many amateurs built linear amps and got powers way above the specified figures, the reasons are the HT level was much higher and the duty cycle enabled short bursts of much higher power.
The humble ECL80 Pentode section will handle 1.3kv on its anode!
Again a true class B stage will deliver more than double the same valve would running class A, sorry to preach to the converted!