>Why not just get a used heater core out of an old GM or Ford and put it
>inline somewhere that it is getting airflow, alternate make a zig-zag
>pipe configuration under your van from 1 1/2 Copper rigid pipe , like
>four uturns three feet long. It will be under your van and in the
>airflow, also out of your way unless you're adjusting your emergency
>brake.

It is Friday, right?

Better yet let's run a copper tube to the top of the vehicle and place an
additional GM radiator in the storage bin of a Westy.  Add a hydraulic ram
that would instantly raise the radiator to an upright position and get the
maximum cooling effect.  Then, once you add your Buick V6, you'll have
enough cooling capacity to cross the Death Valley in July at 100 MPH with no
overheating worries.

Even better, run just straight water in the cooling system, and once the
engine is up to operating temp, you'll be able to take a hot shower under
the spigot you would mount on the side of the radiator.