Surge tank factory srt radiator

Getting ready to plumb surge/overflow tanks on my 71 duster. I bought a motion race works surge tank and overflow cans and with factory 06 charger radiator how do you plumb the surge tank? See the factory surge tank goes to the heater core connections on the back of the engine. I'm connecting those together since I am not running a heater core for now. Should I just t into the lower rad hose or connect to the heater hoses in the rear???