That would be good Robin, thank you. I could widen the radiator space a little, the only real limitation is the sides of the nose cone and the steering shaft. I could probably accommodate 19" wide and 19" high at the sides, a little more in the middle. I don't need a filler cap in the radiator. The existing radiator is very heavy, with four cores. I do wonder if it really needs four cores but...
It would be good if there were some means of calculating the radiators capacity to emit BTU's and a means of knowing what heat various engines need to dispose of.
I have always wondered why the output from the radiator is directed at the engine which the heat has just been removed from! I guess the re-introduction of some fairly diluted heat to the outside of the engine is probably pretty insignificant. By comparison the exhaust manifolds get VERY hot, 250-300ºC. I have seen some manifolds wrapped in insulation but I would have thought that could lead to problems from cracking and only transfer the heat further down the exhaust system where it's perhaps even less welcome.