It's a toss-up. Cooney's stamina was suspect, but I've rarely seen a fighter gas so completely as Bruno. Neither fighter was especially quick. Bruno was a bit better of a boxer, but Cooney was a significantly harder puncher. It all depends on whose tank hits "E" first.
Exactly, its all about the gas tank... Cooney hit a lot harder but Bruno was more skilled... Can Frank outbox Cooney long enough to stop him? I think its possible he could