In a large saucepan, combine sugar, cornstarch, and salt. Beat eggs, and add with 1 1/2 cups sour cream, raisins, and lemon juice to the saucepan. Cook over low heat, stirring constantly, until thickened. Pour custard into pie shell. Cool.
Spread remaining 1/2 cup sour cream over cooled filling. Refrigerate several hours, until thoroughly chilled.