Swap from LA 273 to magnum 408 water pump and cooling

Dana67Dart said
70 and up uses an aluminum water pump.
Passenger side inlet

69 and down uses a cast iron water pump.
Drivers side inlet.

BUT....

you have to use the accessory drive that matches the year.

And on the 69 and older you will need a pass side bolt on timing mark and maybe cut a grove in the balancer for a new TDC mark

thank you...Should I consider using the timing cover and accessories from the original 273, The car currently has all it original accessories. Or is that same timing cover avalible aftermarket?