Its easy to make 1000 hp with a low deck if you aren’t afraid of trying something new.
Slap some turbos, injection, and distributorless ignition on a B engine... you will have all the power you can use with a surplus.
Nitrous, blowers are hard on blocks and cranks.Trying to get over 800 hp on a n/a engine means extreme rpm and ragged edge timing.
You could make 800 hp with a turbo B engine for as long as you could feed it fuel, given a decent tune. Anyone arguing that point hasn’t tried it.