Surface radiators for water cooled engines

Henry "Smokey" Yunick already did.

Corky Scott wrote:
I don't think anyone has any experience actually building the type of
cooling system you suggest. I further postulate that the reason is
because it doesn't work very well, is extremely difficult to fabricate
and co$t$ too much for the supposed (and as yet undetermined)
benefits.

But if you feel you can build this type of system, perhaps you should.
Then you can tell the world about your success.

Corky Scott