Consider this, what if you made the radiator HOSES out of it and made the actual radiator smaller? The heat would dissipate a lot by the time it got to the radiator so the radiator could be smaller and still do the same job. That would lighten the load (some) amd be far less expensive and easier to make. You could also do the water pump hoses as well. That would cool the engine down even more.
But you're right, it's still probably out of our league.
