If you understand hydraulic systems and how they work you will know that oil moving so fast that it can't turn at #4 but can at #3 is someones that does not understand what he's talking about. If a system has 100psi and
you start adding leaks IE rods, mains, cam, lifters the pressure will drop, but the pressure will be the same on the left as on the right at all times because it's a hydraulic system.