Way back I did a dyno test on my 78 Ramcharger with stock 440, all it has for mods is dual exhaust, performer intake and edel 750 carb. It runs great, starts great even in -30c, doesn't burn a drop of oil, but put down a whopping 120-ish rwhp. The compression on these motors is down in the 7's.
A modern rotating assembly and decent heads is the only good way out.