ATI has designed a 6.325? damper for the Mistubishi Evolution VIII & IX 4G63 for high horsepower street & race use. This new design is a direct replacement for the stock OEM damper. The heart of this unit is the tried and true ?damper within a damper? design that has put ATI ahead of the rest. The outer shell is machined to utilize the factory serpentine belt set-up and mounts to the factory crank via a custom hub which replaces the stock timing gear.