I have these, they are for front wheel setups but are so adjustable they may fit the rear as well.
http://www.goldenmotor.ca/shopping/pgm-more_information.php?id=110&=SID#MOREINFO
Gary
I didnt know about the GM torque arms. Those type with the nut and bolt setup.
Ive always simutaed why a torque arm is needed in my head. And thought of what happens when the axel attempts to spin out of the dropouts acceleration or regen.
Edit:
The effect of the pivot on the spinning axel during regen with torque faced forward like the picture causes the arm to push the axel out of the dropout and pull the axel into the dropout during acceleration and pull in during accleration. And when faced opposite the effect opposite . The stadard torque arm may have a different action not having the bolt there.
In any case its wise to do the bolt up very tight at all times.
Oops And on the left side if you use strong regen.And installed like it is in faced the way in the GM picture or in reversed orientation for strong acceleration. I think it should make a difference to these type torque arms.
I would prolly use 2 torque arms.