I have a modern R/D longbow that's shooting a 560 grain arrow at 170 fps.  Would you feel like this set up is adequate for anything bigger than deer ??

          Appreciate any input.

I wouldn't hesitate at all with this set up.  I'm going for moose this year first time with my recurve, have shot 3 moose with my compound.  Using a Black Widow psav 55# @ 28 ", arrow weight around 540 grains 176 fps.  As it has been said before shot placement is important.

elk setups  
  more elk set ups
  moose setups
  black bear setups  

Here are a few old threads that might help you decide...