Hi all new here, I have been running a actual 289hp in a A code fastback, with a early C4 automatic. The problem is a balance issue, lumpy idle that becomes a vibration issue at higher speed, like on the freeway. What is the correct flex plate offset weight, 28oz? or? Running the stock 3.0 gear, Engine is stock with thick dampner, internal offset weight, the engine was balanced during rebuild. I have had the drive shaft reblanced, and on car tire balancing to no effect.