Hi
I edited my previous post and added more info.
Typically the area they work on the most in the bowl, behind the valves. It's not unusual for the ports themselves to be barely touched.
Most people want to just hack open the ports, which is not the way to go.
A "race port" is extremely vague, as most performance talk, but I'm sure as the engine builder knows your desired outcome they will be porting the head as required.
Certainly people make big power with untouched heads, but there is no doubt that a well ported head will make more power everywhere.