A 5 GPM 1/2 HP will do about 3 GPM from 330', with no pressure. If the water pulls down close to 400', that pump will not be able to lift from that far. You may need a 3/4 HP if you want pressure from 330', or water from 400'. A 3 wire motor with a capacitor start box will strart easier from a generator. And you may want to go 240 Volt as it will pull half the amperage and use smaller wire.