Crank Pulley Wobbling?

[Fonzarelli]

I have the march underdrive pullies on my 2000 GT. The Crank pulley is wobbling very noticebly. Will i just need new bolts or a new crank pulley and remove the underdrive one(piggyback style).

I am waiting on a Pro Charger to be delivered to the shop and i dont necessarily have to drive the car.

 

[smokin 04]

i know several people that bought the piggyback style underdrive pulleys and have the same problem. Some are worse than others but they all wobble. My advice would be to only use an underdrive kit than replaces the balancer.