The pads in the past definitely make a visual comparison difficult. Big backs were 225 to 235 back in the 70's and 80's but looked like mountains.
James Wilder was 225 but in pads looks bigger. My favorite clip of him against Nebraska below. Great game, that team was loaded but always seemed to play down to competition as well as up.
https://www.youtube.com/watch?v=yzMil-f8MpE