F2,

The above means that the passages (channels) to the ports are shaped for optimum flow to the intake ports. Also the ports will be shaped to swirl the intake charge into the cylinder, sort of up and around, so as to fill the top of the cylinder, avoiding the exhaust port, to help scavenging.

Did you ever hear of the HB engines with Perry Directional Porting, or PDP? I have a .40 PDP.

Cheers,

CR