Yes, in the front, but is the ride rough when the front is going up (extension of the shock) or going down (compression of the shock)?
Now, "cranking-up" the torsion bars changes only the resting height of the truck (lowers the wheel with respect to the frame). It does not change the amount of travel. Travel is fixed by the geometry of the control arms, the length and where they are attached to the frame and hub assembly. If no changes to these have been made, then the travel is the same as before the "cranking", and the stock shock length and travel is correct.
Are you using the same shocks as before the changes?
I may be wrong, but if I am correct, what is happening is that the shocks have been compressed two inches by the extensions when the suspension has not thereby effectively "robbing" you of two inches of shock travel when the wheel travels up. Bang!
Another possibility is as others have suggested - too much cranking. The torsion bars are tweaked far beyond what they have been designed to handle and the ride would feel like a spring diving board. As an experiment, try de-cranking two inches to see of that makes a difference.