M Roberts wrote:

Now if you can tell me where on a typical single engine airplane you can place a pitot type inlet with a proper diffuser leading to a vertical radiator and then have a perfect exit duct without making a mess on the wing or the front of the airplane, I would agree that it would be the ideal setup.

I was with you up until "perfect exit duct".  What I have planned for an exit duct is probably best described as a 3-dimensional mess.  But I think have the a nice forward end.  See the attached as a rough, undimensioned sketch, except that the largest radiator that will stand upright in this position will be 9x13.  Any suggestions for proper dimensioning?