Originally Posted by VanillaKilla
Looping and Overhand punches definitely have their place in boxing.
Once you have mastered a straight right, you can slightly arc it to slip around an opponents guard or over his jab. Aiming at an opponents temple or ear/jaw area.
I don't think its any less powerful since the body mechanics are pretty similar with both punches (shifting you're body weight by rotating you're hips).
If you're opponent defends against you're right straight by blocking with his left or slipping to his left.... It only makes sense to slight arch you're punch
This. Some fighters such as Rigondeaux almost exclusively throw their rear hand as an overhand punch. Look at Marquez' first knockdown in the recent Pac fight. The best punch Antonio Tarver ever threw was an overhand left, pretty impressive for an 'arm punch'