Equal compression means equal balance. Means much more then you think in performance. Run an engine with a dead cylinder and feel the vibration. Lower compression in one cylinder may not be felt by your butt. But the crank feels just a tad difference. Every little bit counts when on the bottom on a hard pull. And at the top in RPM's. Balancing is the most crucial of an engine performance.
Take any Engine or electric motor and just through the balance off a bit and see if it reaches the same RPM's . I remember when I was young balancing my slot cars engines on two level razor blades.
Put 1 drastically different smaller CC head on an engine and see what happens to the performance. It will not increase from the higher compression from the one smaller CC head it will decrease.