Oliver McCall's Chin And Power

Yes, his heavy punch and iron chin can both be attributed to his heavy bone structure.

McCall wasn't an exceptionally big puncher or anything so I don't think his hands had much to do with anything. Maybe they made his punches abit more stable and powerful though. I think he could just naturally take a very good shot. Dude's head was screwed on with the bolts of Zeus...

I guess it could, having heavier hands. People used to say that a lot of Liston's power was in his unusually large hands, I don't know how big they were, but he had to have special gloves made because his hands wouldn't fit into the normal ones.