I do find it interesting that when you search "broken crankshaft" you'll find discussions around the Fluidampr brand. Even some of the threads at Speedtalk discuss this. Makes you think....
Funny that I never broke anything when running them...and thats up to 8600 rpm.. EDIT its been on 3 engines now.. 340, 396, and now my 416... I'll let you know when I break a crank