You can easily make one of these with some flatbar or angle iron. Just lay it across the torsional damper, mark and drill your holes, and voila. You might have to notch out the center a bit so there will be room to fit your socket for the dampner bolt. I used 1 1/2" steel flat bar to do my 2JZ-GTE dampner.
It'll need to be braced on the floor or your engine stand and/or be at least 2 feet long to get some mechanical advantage when you torque it down.