Carnera is by no means an easy opponent stylistically. Many people dismiss Leonard's comment about Primo's defense as a pre-fight build up or insignificant praise (granted, I don't take the word marvelous literally here; it was more of a gentleman, british-esque exaggeration), but I do think that although limited, his defense was deceptively effective. Fighting with his right heel up most of the time (always ready to lean back/step back if necessary) he preferred to keep an opponent at bay with hard jab and remorselessly tie him up if he got too close, roughing up with uppercuts and body punches once in clinch. 260 lbs mass of muscles that actually knows how to wrestle is not an easy obstacle to get past and Carnera did know how to tie a man in. His hands usually moved forward resembling long guard at times: he would either parry, catch an incoming blow on the gloves, or go for a leverage guard (visibly less refined and purposeful than that of Foreman or Saddler, understandably, but effective nonetheless) and subsequently clinch. Despite relative lack of good, natural boxing instincts, immobilizing elbow joints and manipulating an opponent once he got his hands on him did seem to come naturally to him. That being said, due to being a late starter as well as being a big man in times in which, in my opinion, size in boxing wasn't yet exploited and understood to its fullest potential, he clearly had deficiencies. At the end of the day Primo was a super-heavyweight prototype; the first notable blueprint; the bare bones of what would decades late become a dominant "style" if you could call it that way. Rocky however is simply a different kind of champ and a different breed of fighter. Best case scenario is probably Carnera putting up helluva fight and gaining people's respect in defeat.