I've not proof read this so apologies if there's any errors, but it's a quick summary of the weight difference every time the Heavyweight Championship of the World changed hands. Sullivan vs Corbett=-34 pounds Corbett vs Fitzsimmons=-17 Fitzsimmons vs Jeffries=+29 Hart vs Root=+19 Hart vs Burns=-17.5 Burns vs Johnson=+25.5 Johnson vs Willard=+13.5 Willard vs Dempsey=-58 Dempsey vs Tunney=-0.5 Sharkey vs Schmelling=-9 Schmelling vs Sharkey=+17 Sharkey vs Carnera=+59.5 Carnera vs Baer=-54 Baer vs Braddock=-16.5 Braddock vs Louis=+0.25 Charles vs Walcott=-14 Charles vs Walcott=+12 Walcott vs Marciano=-12 Patterson vs Jackson =-8.5 Patterson vs Johansson=-14 Johnansson vs Patterson=-4.75 Patterson vs Liston=+14 Liston vs Ali=-7.5 Frazier vs Ellis=+4 Frazier vs Foreman=+3.5 Foreman vs Ali=-3.5 Ali vs Spinks =-7 Spinks vs Ali=+20 Holmes vs Ali=-6 Holmes vs Spinks=-21.75 Spinks vs Tyson=+6 Tyson vs Douglas=+11 Douglas vs Holyfield=-38 Holyfield vs Bowe=+30 Bowe vs Holyfield=-29 Holyfield vs Moorer=0 Moorer vs Foreman=+28 Foreman vs Briggs=-33 Briggs vs Lewis=+15 Lewis vs Rahman=-15.5 Rahman vs Lewis=+10.5 Vitali vs Sanders=+10 Wladimir vs Chagaev=+15.5 Wladimir vs Fury=+1.25
Carnera vs Loughran was a record IIRC, although I CBA checking and I don't think it was a title fight.
