Well Tommy Hearns started out at 147 and went all the way to 190 so i say he was just as powerfull i guess but dont forget what age Pacman was when he started he was 16 thats reason the weight was so low Mayweather was at that weight when he was that age in the amatures. I mean even Oscar when he was younger was in the 130 division which was not his real weight just a thought when people talk about weights you got to remeber the age at which the fighter started.