2021 Ram 3500 H.O.

I'm not understanding why an increase in the stroke of the camshaft is needed to increase pressure if the CP3 is already pumping more fuel than the CP4 is per revolution. Obviously I realize that volume and pressure are two different things. I also realize that the higher pressure is needed for emissions where as power is mostly concerned with the volume of fuel. However, pressure and volume can be related. For instance pumping more fuel through an orifice will increase the pressure. There has to be something regulating the fuel pressure. My understanding is that the fuel pressure is controlled by the volume of fuel fed into the top of the pump. Basically the injection pump acts like a variable displacement pump because a controlled amount of fuel is fed into the pump rather than by mechanically varying the pump's displacement. Really what is important here is that the CP3 has a much better more reliable bottom end that is much less prone to failure and even if it does fail it doesn't pump debris into the high pressure side of the system destroying the entire fuel system. The CP4 is a poorly designed cheap pump.