I pick Duran. I think Mike was rather inexperienced at the time, and Duran was better than Mannion. It would be close, but Duran would be in the fight and love the infighting. Mike would be faster but Duran I think stronger in his punches, since he would place them well. I think Mike's style works well for Duran to stay in close.
Duran of the Moore fight could beat that version of McCallum due to the massive experience advantage, but it wouldn't be easy. A couple years later though, McCallum was at this 154 best and would win without much trouble.
When could it have happened? 1984 Duran chose to fight Hearns and at that time I don't think he was aware of McCallum. Mike didn't have a name yet.
McCallum was Duran's mandatory and he had to fight him before fighting anyone else. Duran took up an offer to fight Hearn's for big money and Hearn's WBC title. The WBA stripped Duran and McCallum fought for the vacant title. McCallum wasn't making any big waves and Duran was always going to take the bigger money and make hay while the sun was shining.
McCallum was such a non-draw (unknown) at the time that Bob Arum picked up the purse bid for Mike vs. Mannion for the vacant title for a grand total of $70K. I guess Mike got the bigger split since he won.
McCallum had too much height and reach, he would have landed a lot to Duran`s soft body, Duran looked a little slower at 154.
He was always a non-draw. ‘What would he bring?’ Barry Hearn asked when the boxing press put forward McCallum as an opponent for Chris Eubank (in the post-fight press conference after Eubank’s blockbuster event v Gary Stretch). ‘Danger’, someone said. ‘Well, we’re looking at returns at the box office,’ replied Hearn.