Champions Mike Tyson and James (Bonecrusher) Smith,...

Champions Mike Tyson and James (Bonecrusher) Smith, considered the hardest-punching heavyweights, will fight March 7 at the Las Vegas Hilton in the next-to-last step of the division’s title unification series.

Tyson won the World Boxing Council title Nov. 22 with a second-round knockout of Trevor Berbick. Smith won the World Boxing Assn. championship on Dec. 12 with a first-round upset knockout of Tim Witherspoon.

Tyson is 28-0 with 26 knockouts, and Smith is 19-5 with 14 knockouts. Tyson, 20, the youngest heavyweight champion in history, has been made a 7-1 favorite.