Tight LCAs produce earlier intake closure after BDC.
If increased duration is the only change, then the longer cam normally robs power from the bottom end of the rpm range and adds to the top.
When only cam duration changes there is usually little change in peak torque.
All the longer period does is move the point of peak torque up the rpm range.
Most of the increase in horsepower occurs in the upper 30 to 40 percent of the rpm range.
Increased valve flow area in the first half of the induction stroke has significant importance for many reasons.