If this is a street-driven motor, use an OEM-type damper with an elastic material between the hub and the outer ring. Here's a good source...
http://www.damperdoctor.com/

If you will be drag racing and going quicker than 10.99 seconds, you'll need a damper that's approved to meet SFI spec 18.1, such as a Fluidamper, Rattler, etc.

Running the motor without a damper of some sort will allow the crank to destroy itself due to uncancelled harmonics.

The exception is a blower motor using a drive belt off the crank, which tends to cancel harmonics (ala Top Fuel, Funny Car, etc.).