In a heavy medium saucepan stir together the sour cream, 1-1/2 cups sugar, flour, egg yolks, and raisins. Cook, stirring constantly, over medium heat until thickened and bubbly. Keep warm.
For meringue, place the egg whites and cream of tartar in a large mixing bowl. Beat with an electric mixer on medium speed until soft peaks form (tips curl). Gradually add 3/4 cup sugar, 1 tablespoon at a time, beating on high speed about 4 minute more or until mixture forms stiff glossy peaks (tips stand straight).
Pour warm filling into baked pie shell. Spread meringue over filling. Bake in a 350 degree F oven for 15 minutes. Remove and cool on a wire rack for 1 hour. Chill 3 to 6 hours before serving; cover for longer storage.