See the word "POTENTIAL", I used a 25% increase in capacity will NOT show 25% more power, as frictional losses increase with larger longer heavier pistons, reciprocating mass increases too due to component weight.
Enguine capacity is very carefully chosen to do the job that the car manufacturer wants, the smaller the better, needs to be just big enough, as smaller engiunes due to the above and other reasons have better VE that is why there are turbo cars out there, a 2.0 pinto has less EC than a 2.0 turbo car.
Air speed is another very important consideration, smaller ports increases VE whilst EC can be increased with supercharging ie turbo.
tabetha
ps this is going to be a long one!!