Heat Exchange in a RV Troopie

I went to fit the heat exchange for the shower on the 78 Series Troopie and it does not fit where it did on the 75 Series

On the 75 it fitted on the lip near the fire wall over the top of the motor. On the 78 the rocker cover is bigger and there is a pipe that goes from the crossover pipe around the back into the exhaust manifold.

The front of the motor is out as well near the oil filler cap, again the rocker is too high.

I was thinking about just behind the head light on the passenger side. Vertically mounted with the top near the battery or behind the winch on a bull bar. I can mount it there out of the way but I am worried it might act as a cooler and not allow the heater to work properly. Last year I was away for winter up north and will be again this year so the heater might not be required.

Any other ideas of where to fit the heat exchange? The engine bay is standard, factory turbo diesel, except for the dual battery set up on he passengers side.

Wayne