In The Burning Crusade it is item level 146 and requires level 70. In Wrath of the Lich King it is item level 146, requires level 70 and sells to vendors for 1c. In MoP Classic it is item level 146, requires level 70 and sells to vendors for 1c.
Read from the World of Warcraft client build files.
How Vengeful Gladiator's Plate Helm Compares
Who It Suits
Plate is the armor type Death Knight, Paladin and Warrior wear. With Strength or Intellect, Vengeful Gladiator's Plate Helm suits Arms, Fury and Protection Warrior; Holy, Protection and Retribution Paladin; Blood, Frost and Unholy Death Knight.
Transmog Sets
Vengeful Gladiator's Plate Helm is part of the transmog set Vengeful Gladiator's Plate Armor (Warrior only). The other 14 pieces:
Items Numbered Next to Vengeful Gladiator's Plate Helm
Blizzard numbers items as they are created, so the named items next to ID 33730 (33725 to 33735) were usually added in the same batch as Vengeful Gladiator's Plate Helm: the same quest line, zone, vendor or reward set.