help strokeing a 225

hey, i have a 225 slant six that i had bored a little over stock to increase the compression ratio, it has a holly one barrel, but i want to go to a four barrel, my question is how much horse power will i gain if i go with an Offenhauser Slant Six 6 4 bbl Intake Manifold and a holly 4 barrel? would this be worth doing?