Might also consider a quick ID / OD check of the damper and the crank. Also, compare the new damper's ID to the old.

Since the damper aligns to the OD of the crank and the face of the timing belt cog, I would take a look at those surfaces as well.

Is it possible that your new pulley is machined out of spec?

87 Turbo Intercooled Raider, roller cam, torsen rear diff, LSD front diff, lockup auto with modified converter, V6 brakes, low transfer case gears...