This would have been an interesting styles match up and a fight that could have happen during the late 1980s. They both beat Iran Barkley in a MW title fight as well.
Yeah, Kalambay is as bad it gets for middleweight Duran. It'd be a similar schooling to Benitez-Duran.
This fight is winnable for Duran if he has a "best night of his life" fight. Like he did with Leonard, Moore , Barkley and Hagler. Most guys only get one so maybe Duran would get a 5th but I wouldn't bet on it.