The Defender heater which was also fitted to non AC countys to comply with the Australian Design Rules. The heater itself will bolt straight up and the intake ducting. you can leave the county dash alone or pull it out. If you leave the county dash in it you can still use the controls to operate the heater but the heater doesn't have the vacuum valve to turn the heater tap on and off the defender on had full water flow all the time and there is a flap in there to stop the air being forced in when you don't want it to. All the bit are available and should bolt up. I'm in the reverse process I have pulled out the heater and fitted an AC and am in the process of setting it all up.