Electric or Hydraulic torque wrench

Hytorc's work great Valve makers use little ones & turbine makers use big ones - be sure to use never-seez!

I don't have experience with hydraulic tools . According to their website, Hytorc tools are used to preload fasteners with zero torque. They are much slower - minutes per fastener.

Electric tools use torque to preload fasteners. They are much faster - seconds per fastener. Good suppliers for these are AtlasCopco and Stanley. You can learn more at the following sites:

You can buy pnuematic torque wrenches as well as hydraulic and electric. There is also manual torque wrenches capable of this torque which is the cheapest of all. Depends a lot on how you want to torque the bolts. Are you going right up to 500 ft/lb or working your way up in 3 or 4 steps while also torquing other bolts in a sequence, such is done on a pipe flange.
If I was out in a field I would obviously use the hand wrench, in a shop with an air compressor I might use a pnumatic torque wrench.