Using a disc brake master cylinder in a drume brake car.

Is there a problem with using a disc/drum brake MC in an all drum brake car? Specifically a '72 Scamp with 9 in drums all around. I have a few A body disc brake MC's sitting on my shelf. Some one told me that brakes will work better this way. All other components (lines, hoses,wheel cyl.) are stock & in good working order.