If a Magnum engine is dressed out with LA timing cover and water pump the lower hose would be whatever correct part number is for the application you set it up to be.
If the car has a correct size and style radiator with right side water outlet it will need a later style right side water pump and lower hose to match.
If the car has a correct size and style radiator with left side water outlet it will need an early style left side inlet water pump and lower hose to match.