Need a new balancer

I'm going to take the Dart to a car show tomorrow. So when I took the cover off and cleaned her up, i noticed while the engine was running ,I have a slight wobble going on of the harmonic balancer. I'm going to make sure the bolt is tight in the morning but I'm sure the outer ring has moved on the hub. My question is what is a good brand of new balancer? This is just a cruiser with A/C ,P/S 360 Auto.