drum brakes and moser axles

It says it right in the item description what you need.
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Part # A30-CST-A45 - A-Body, 8 3/4" Rear Axle Shafts, Stock A-Body Drum Brake (Redrilled) -- 30 Spline
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You need to use the stock A body drum and drill, or open the holes to 4.5" pattern.

If you have the small bolt backing plates and drum, you got what you need.