Mix in saucepan: sugar, flour, salt, and 1 3/4 c. reserved juice. Bring to a boil. Beat eggs well. Add to boiling mixture, cook 1-2 minutes longer at reduced heat, stirring constantly. Cool completely. Mix cooled pineapple juice mixture and cooked pasta. Refrigerate 3-4 hours add marshmallows, mandarin oranges, pineapple and cool whip. Mix well. Chill and serve.