the thing that sucks about a 305 is they are the same stroke as a 350 but a smaller bore, so they are heavier. the 302’s had the same bore as a 350 but a tiny stroke, hence why they like the spin high rpm’s.
they also never put a decent set of heads on 305’s. So maybe with a fuck ton of compression, the fully ported heads and the right cam/intake/carb combo, i guess. but its so much easier to make power with a 350. also i don’t believe the 305’s ever came with a 4 bolt bottom end, so spinning them at high rpm’s isn’t the greatest idea in the world.