So I was bored. If the Marvel wiki is to be believed, Iron Man can lift ~100 tons. So I dusted off my 3.5e Player's Handbook and went to the carrying capacity chart. I followed all the rules of calculating carrying capacity based on strength, and simply reversed the process. And the result is in the title, a 500 strength stat. That means he gets an extra +245 to his melee attack and damage roles!
For a little comparison, Asmodeus the lord of the Nine Hells has a strength of 40. A Great Wyrm Red Dragon has a strength of 45. Kord, the god of strength, has a strength of 55. So, uh, Iron Man OP!