Harry Greb had only 44 kos, a low ko rate, but he fought above his weight class a LOT. Its hard to have a lot of kos when you're giving up a lot of weight to your opponents. So maybe he had more power than his ko record would indicate?
He rarely sat down on his punches, relying on his speed and volume of punches to out-point and occasionally wear down his opponents. There are instances of him showing legitimate KO power when he did decide to put full torque on his blows, though, namely the first round KO over Heavyweight Gunboat Smith.
