Compression ratio vs Porting

To expand on the same twist. More flow at lower lift increases "area under the curve" making more power for a given cam profile. A good valve job and blended bowls will help low lift flow, so will bigger valves. Bigger valves with a good valve job will help even more. Rebuilding those "302" heads with 360 valves (1.88/1.60) and a good bowl blend will really wake up a 318. Don't go too nuts on the cam, one of the modern 268 profiles would make for a really nice street combo.

But, to answer your original question getting 10% more air (and FUEL!!) into the cylinder will make more power than squeezing the same amount 10% harder before you light it.