Blend 3/4 cup orange juice, 2 tablespoons cider vinegar, and 1 envelope salad dressing mix in an electric blender container.
Add 3/4 cup salad oil and blend.
Peel 3 fully ripe avocados and cut into pieces.
Adding a few pieces at a time to the container, blend in avocado.
Mix in about 1k cup dairy sour cream.
Remove to serving dish; cover and chill.