I have a friend who had a blown 468 break the crank snout twice and the machinist said it was due to his fluidampr. He removed it and went to a drive hub with his new crank and he never had another issue. I've also had a couple high rpm 12v 5.9's break cranks at the first journal with fluidampr's. This only happened when a tcase blew up and the engine flared past 5500. The extra weight and inertia of the fluidampr was the only thing we could see that would cause that. We switched to ATI after that.