Instead of fighting I think they'd just fuck some strippers. Floyd would slap the strippers around, then Monzon would chuck them off the balcony.
Depends upon which Floyd shows up. If it's the Welterweight Floyd, Monzon would be too big. If it's a Floyd enhanced by the same Super Soldier serum given to Steve Rogers in which he grows 3 inches taller, puts on 13 pounds and is proportionately the same otherwise....Monzon is dominated.