[jdean]

If you are using the standard LS 4-link setup, you MUST use a panhard rod.

This setup is similar to the traditional straightline hotrod, roadster 4 link. If you do not use a panhard here, there is nothing keeping the rear end in place from side-to-side.

It is different than the late model Mustang 8.8" triangulated 4 link that does not need a panhard.

Look at which set-up you have and you can answer your question.

John