Prep yeast according to package directions.
Once yeast has been proven active add the 4 cups of warm water, molasses, salt, sugar, melted margarine and combine together.
Gradually add flour, stirring it in until you can handle it easily.
Turn dough out onto a lightly floured surface and knead it until it forms a smooth ball. Place into a lightly greased bowl, rotating dough so that it is evenly coated. Cover with a damp cloth.
Let rise until double in size.
Punch down and form into loaves. Place in lightly greased bread pans and let rise again.
Bake at 350 F for about 40 minutes.
Brush tops of loaves with butter/margarine.