Is anyone else curious

It’s not like I need the extra work but curiosity may drive me to it. I have never flowed or checked the airspeed on an Edelbrock or Speedmaster head with a Ferrea exhaust valve. What do you think. Is anyone else interested. These heads gotta get finished by mid week hopefully but this may be worth the extra 10-15 minutes.
Yes please. Never paid attention to those valves but all the high end stuff uses the it seems. Fill us in. What makes them so good?