1st autocross run.

A panhard bar would locate the axle effectively. However, it will make the car behave differently in left and right turns because it attaches to the axle at one end. IMO, a Watts link works better because it attaches at the center of the axle and has equal effect at either end. The problem is going to be mounting one on an 8.75" axle housing. Another problem is going to be sure that it does not interfere with your tail pipes and rear anti-roll bar (if any).

I ran one of these on a NASCAR Sportsman short track car back in the day. We quit chewing up the inside of RH tires and the practice was banned the following season.