Who would do better against the 200lb + Heavyweights post 1960 R Marciano or A Moore

I will make a number of point here:

1. It is debatable whether Duran was a swarmer, but we can stick a pin in that.
2. Duran was a former lightweight, so he should never have been expected to beat the best welterweights and middleweights in the first place.
3. Most of the fighters who beat him were heavy punchers. You have a much better chance against a swarmer, if you can match them in terms of firepower. If you can't then they have much more chance of imposing themselves.
4. The results that Duran got against much bigger fighters, could be seen as validating my point in many ways.