I like Tiger by decision. McCallum was a good all-around technician, but didn't really excel in any one area. He didn't have the quick footwork that other boxers like Archer and Griffith used to trouble Tiger, and I don't see him being able get in through Tiger's tight guard and work his body, which takes away McCallum's bread & butter. I think this would look somewhat like Tiger's win over Benvenuti, with Tiger using his footwork and counterpunching ability to win a clear decision.
After one of the more grueling bouts in MW history, Tiger by UD. His more effective stance and harder punching is the difference here.
In an unspectacular, workmanlike performence, Dick Tiger would win a decision over Mike McCallum. Mike would start off fast, like so many of them did against Tiger, only to slow down and get caught alot and outworked in the late rounds, and lose on points, 9-6 (fairly close) in rounds. No kds would be scored, but Tiger would clearly be the stronger man and would finish fresher than McCallum.
mccallum is one of my favourites but i will go ud for tiger better work rate over over the later rounds