Morales of today wouldn't have a chance in hell against Marquez so much less against Mayweather, he only looked good in his last performances cause he fought a young unknown green kid, and against a slow limited Maidana, both guys were pretty much made for him, but Morales doesn't have the speed, reflexes, or durability to hang with Mayweather at 147

if it was Floyd vs Morales back at around jr. lightweight well then yea it'd be a different story, not saying he would beat Floyd but it would be competitive