If you are using a steering set-up where the drag link goes from the pitman arm to the drivers side spindle, then Henry Rifle is absolutely right---it doesn't matter. BUT---If you are using a vega cross steering set-up it does---here's why. The vega box and Pitman arm are effectively "fixed to the frame" on the drivers side. The other end of the drag link is attached to the spindle arm on the far side of the car, so by default, it is attached to the axle which moves up and down as the spring flexes. In a situation like that, your panhard rod should be fixed to the same framerail (drivers side) as the Vega box. Even with a perfectly engineered panhard rod, the body will move slightly back and foth as the rear spring flexes, and the panhard swings thru its arc. Normally, it is such a small amount that it is not noticable. ---However, if your rear Panhard rod is attached to the passenger side frame rail, it will exagerate this side to side moment, as it is working opposite to the panhard rod effect at the font of the car caused by the drag link.---Y'all clear on that now????