We went with dual-piston Ford F-250 calipers and custom heavy-duty caliper mounts. However, the ID of the mount was too small for the OD of our axletube. We just wanted to Jersey-rig it and torch the hole bigger with an oxy-acetylene, but we were vetoed by Off Road Evolution. Their reasoning is that if you torch-cut the bracket, it might not sit square on the tube, or the spacing from the rotor might be wrong and possibly result in vibration. In the end, it usually pays to do it right the first time.