Grandpa's  Blue Cheese Dressing

1 quart mayonnaise
1/2 c. miracle whip
1/4 tsp. Lemon juice
1/4 tsp. Salt
1/4 tsp. Pepper
1/4 tsp. Sugar
3/4 tsp onion powder
1/4 tsp accent (MSG)
1 c. buttermilk
1/4 tsp garlic salt

Mix together and refrigerate in tightly closed container.