Re: p4p heavyweight
Pound for pound doesn't really enter into it with heavyweights! From around 185 lbs. on up, it's anyone's game. Beyond a certain limit, size and weight don't add any advantage.
So the list remains the usual suspects: Sullivan, Corbett, Johnson, Dempsey, Tunney, Louis, Walcott, Charles, Marciano, Ali and many names between and since.