I can't help answer your question about wire routing, but I may be able to provide a little inspiration with the following photo. It's a hotrod I saw a few years ago. At first glance I thought the owner had put one of those mock up plastic engines in place until he could finish the car. On closer examination, I discovered it was a finished and fully functional car. Everything that could be hidden out of sight (e.g., radiator, water pump, coolant lines, fuel pump and lines,
oil filter, ignition lines and components, fuel tank and filler, etc.) appeared to be missing. I've seen engine bays that looked clean because they had all sorts of covers on them, but this was the cleanest one I've seen that was out in the open.
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