I want to point out the way that Joe is punching. He is driving the hand not like the modern boxers slingshoting them! His hands moves first and than his body. We can see this type of punching really clear when we watch Forman and Moore. I hate how some comentators are talking for Formans technik saying that he is punching only with the hand, but actuially it is the oder way around. Not only he is punching with his whole body, but his accurasity is extreamly high becaus it is much more easier to hit some one with only the hand and after that to drive trough with the body.
Just watch the 1-2 combos. How unortodox they look in the modern days...
The oder thing that i really like is how he is carrying all the time his elbows down. Everything is streight compact. It is almost impossible to beat him to the punch.