Strongest in what sense? H2H its difficult to give the 70s heavies much chance against later eras due to the huge size gap. The current era is probably H2H the best era ever.
1991 Annual Heavyweight Rankings... Evander Holyfield Mike Tyson Riddick Bowe Razor Ruddock Ray Mercer George Foreman Tim Witherspoon Tony Tucker Lennox Lewis Michael Moorer nuff said.