ROFLMAO Rocky's chin was tested in every fight he had. He led with his face. Wlad has no chin Manny knew that that's why he developed Wlad's clutch & grab style. Some of the best tested Rocky's chin it never failed him once. My old buddy Tex Cobb summed it up When he said " I have the best defense in the world, my face. Beat on it all you want till you get tired then I'll knock your a$$ out" lol
Marciano never fought power punchers on the level wlad has.If anything size for size Marciano probably has the better chin but can see Marciano getting stopped by punchers like Peter and sanders as well.Any fighter over 230 will have some sort of power to them,LHW Moore dropped Marciano so we can all assume whatever.