....that "pressure port" is used to pressurize the fuel. When you supercharge an engine
you drastically increase the air flow into the engine. In order to get enough fuel into the
engine to get the proper fuel/air ratio when it is being supercharged (with air) you must
have a way to increase the fuel flow to match. This method works in a manner in which....

...as the boost is applied to the engine, the same ampount of boost (pressure) is applied
to the fuel (pressure). As the RPM (and boost) is increased, the pressure to the fuel is
increase the same amount. This is a way to get around the added complication (and expense)
of having fuel injection added to the engines as well.

FBD.