IF he had competed in his athletic prime or his peak he would have MAULED just about anyone. It was not just his strength but the way he turned his hip into the punch. He had good form and with his power he could change a fight with one punch.
There really was not as heavy a handed fighter as Carwin (IMO) in the HW division ever, aside from people that could kick. He could ruin you with a cross right. He didn't have the best boxing skills, but the man was a MONSTER. He had decent wrestling, ok boxing but really good dirty boxing, uppercuts and elbows. It's too bad he never fought Cain. Cain would have cardioid him to death unless Carwin caught him early.