MBHD Airspeed in the port will be dependent on demand vs' cross sectional area and length. The "Mach" number will vary along the entire port with the density of the fuel air mix and temp.
It is true that going over a certain "Mach" number will take more energy than you get back and at that point you would start to try to slow down the air. That is why sometimes engines will make more power with a port that is larger that flows no more air than a smaller one however they do become much more camshaft sensitive.
As to the 2 sq. in. port on the respective engines that would depend assuming the same manifold then the camshaft is what will determine the airspeed for each combo. As you add duration the airspeed at any given RPM will drop in the port. So each one of the displacements with the same port area could have similar velocities at the same RPM given different cams (larger In the larger engines)
