Michael Moorer. WBA, WBO, IBF Heavyweight champion of the world(1992-1994). Former WBO light Heavyweight champ(1988-1990).
From April 5, 1915 to July 4, 1919 - Heavy weight boxing champion - Jess Willard ( American )
Wasn't Wladimir in as champion at that point(?)
Unfortunately there is no undisputed heavyweight champion.
The current heavy weight champion of boxing is Vladimir Klitschlow. He is from the Ukraine and weighs 243 pounds, or 220 kilograms.