Preheat the oven to 325 degrees F (165 degrees C). Soak raisins in boiling water for 10 minutes. Drain, and chop.
In a medium bowl, cream together the sugar and butter until light and fluffy. Beat in the eggs one at a time, mixing well after each one. Stir in the vanilla, sour cream, walnuts and chopped raisins. Pour into the baked pie shell.
Bake for 30 minutes in the preheated oven, or until firm in the center. Allow to cool completely before slicing.
