More displacement or more number of cylinders

Hi sir my name is ali I am mailing you to ask one technical question there are two ways to increae power of engine one is to increase the size cubic capacity cc (cylinder size)of the engine and second is to increase number of cylinders there are 6.0 litre v8 and there is 6.0 litre v12 which got more power and what the main different between v12 and v8 when both engines have same 6.0 litre dispalcement well waiting for your reply thanks indeed