I need to add some water returns to my cooling system and want to make sure this will work before drilling holes in my Griffin radiator.  I need to return water from my heater core and Fluidyne heat exchanger to the suction side of the water pump.  My plan is to drill a couple of holes in the end of my radiator and weld on a couple of AN / NPT fittings to attach the hoses to. 

From what I have read and seen in the past, the heater core return on the car goes right up into the neck of the water pump housing.  I am not a systems expert on this, but my simple brain sees no reason why I shouldn't be able to bring both these returns to the side where the hot engine water enters my radiator.  This will will allow them to pass through the radiator for some cooling prior to entering the pump housing and cycling through the system again.  Since Mazda didn't configure their system like this, it does leave me wondering if it will work okay...

Thanks for any information...

Doug Lomheim, RV-9A; 13B
(Leaving Key West today for home and more fun on my 13B FWF!)