The magnetorqe on the 790 is really jerky. I've tried adjusting it and cleaning everything up but no luck. The 670 however is really smoothYes hard , with those helicopter windows. The magnatorque swing is nice and the drum dogs are handy to stall the torque against for fine lowering. Nice old cranes you have there to ryanmueller. I run Americans mostly tough cranes but rough on the swing unless they are the hydrostatic ones