[PeterAllen]

Rob – a few photos might help. I think that as long as the radiator output is always below the water level in the radiator then you would be okay, irrespective of were the radiator is. With my donor LS1 (VZ SS Ute) the radiator was always full and any expansion and contraction of the water volume in the system, due to temp fluctuations, was addressed by coolant flowing in and being sucked out of the reservoir tank which is not pressurised. I theory I could have the radiator output anywhere on the radiator.

When I ran the engine I use a plastic container as a reservoir and it all seemed to work okay.

You always have the option of relocating the input and output; just cut them off, weld a patch over the hole and weld on at a new location – after you have cut a new hole!!