Hi
The best place for air flow is in the front, a guy on another forum (look for use name Baja Wes on
http://forums.aussieveedubbers.com) I visit fitted a V6 Mazda motor to a Baja with the radiator above the trans, he has over heating issues at higher highway speeds.
On my old 1302 I ran 1.5 inch stainless tubes to the front of the car, they followed the chassis bolts under the pan, my car was pretty low and I never had an issue with them hitting the road.
Steve