Although the EMG-85 Humbucker has more measurable output than the 81, its frequency response and string interface are different. The 85 uses 2 Alnico magnet-loaded coils with a wide aperture to maintain a beefy low end and a fatter top end. Because of a more natural tone, it works great as a rhythm and blues pickup because it has loads of output but isn't muddy. It's a perfect choice as a rhythm pickup in combination with an 81 in the bridge. 

The midrange has great definition and doesn't get foggy or muddy in the rhythm position. The EMG-85 guitar pickup works best if you like the natural distortion that comes from overdriving the front end of your amp. Under any condition, it responds accurately to your technique.