As
saying among people who know
internal combustion engines. To have an
engine produce more power, you have to get it to burn more
fuel/air mixture in a given amount of time.
The easiest way to do this is to simply have more
displacement, more space to hold the
mixture. Now, it's possible to
bungle even a
motor with a lot of displacement (normally measured in cubic centimeters nowadays), like, say, a 1200cc
Harley, can be
enfeebled if one really goes out of one's way to do so.
However, in modern engine design, there simply is no substitute for size. You can add turbocharchers, more valves, better cam configurations (allowing for more RPMs), better fuel, lighter components, whatever you can think of. But bigger is better.