[foxtrot3]

Hi. I dont know if it is possible on the AU as from memory it has 3/4 heater hoses but if you can find some reducing hoses for both sides of the heater try to run the 4 way heater tap from a holden and get rid of the t pieces. You run the heater hoses from the heater outlet on the head to the tap then to the core and then return to the tap and after that to the gas convertor and finally return to the water pump. When the tap is on all water goes through the heater first then to the convertor, when the tap is off the heater core is bypassed and again all water flows to the convertor. Cheers MD