Crank whip is one of the harmonic effects on the crank especially at high RPM. It is the crank bending /squirming in the bearings that the crank does..not adequetly quelched by the stock damper...

1999 Amazon Green SVT Contour (#554/2760)
Stock SVT Duratec V6 with:
Intake- K&N filter/75mm MAF meter
Exhaust- MSDS Y-pipe/Bassani catback
Durability-Ford "dual mode" damper, Mobil 1/K&N oil filter
179.2 FWHP at 6900 RPM