Nice job and nice thread presentation.

And a little OT, I have always pondered the original concept of a fan shroud. Is it to move air by the engines fan thru the largest area of of the radiator by the fan, or is it to make the fan move the most amount of air thru improved efficiency by good shroud design (ie a simple tight fitting ring), albeit thru a smaller area of the radiator?

Seems to me the first goal would be best for low vehicle speed use, and the second more ideal for high speed use, since it would present less blockage of the radiator since most shrouds reduce airflow area at some point. However simply over sizing the radiator would, imo mask whatever results one observed to the above solutions