How Many Horses does your Posi eat?

In my opinion going down the 1/4 mile there is no horsepower loss attributed to the sure grip/posi no matter who makes it. The horsepower loss is through the gears and bearings in other words turning friction. The Ford 9" I think is the worst cuss everything's so stiff (ya ever tried pushing a car with one in it) followed closely by the dana then the 8 3/4. I've heard of numbers between 10-20 loss through the Ford.