Spinach Salad

from Tiffany Whitney
This makes a huge batch:
1 bag spinach
1 to 2 heads lettuce
½ pkg swiss cheese grated
1 jar Hormel Bacon pieces
Sliced mushrooms
Dressing:
1 ½ cups oil
¾ cup sugar
¾ cup white wine vinegar
½ tsp salt
1 ½ tsp. Onion salt
¾ tsp. Dry mustard
¼ tsp poppy seeds