They are a point in time. They were a way to boost port velocity (they are basically only half the width of a conventional port by the time you reach the valve). With that velocity and swirl comes a boost in low rpm torque. But like running a marathon with your nose half plugged up, they don't breath well at higher rpm. They served a purpose...with TBI, they gave very crisp throttle response, and very good low end torque.
Time marches on, and the next generation of SBC engine uses Vortec heads, the best iron SBC head GM ever produced...they had learned a lot about head flow and chamber designs in this time. They also gain roller cams of a more aggressive profile Vs TBI, and multi-point fuel injection. So torque and power are up.
In this case, newer is better, but that doesn't mean older is garbage. It just depends on your goals.