Electric fan won't cool at highway speeds

The other problem with radiators..........I seemed to have had...........OldmanMopar once posted that he believes the FINS can crack loose from the TUBES and do not transfer heat, even thought he rad is clean and flows good coolant

I seem to have had this with the original rad out of my (original) 273, then later put a /6 used rad in out of a slant, (now) in front of a mild built 318. INSTANT cooling!!!

Both were 2 row cores

Unless you rigged up some sort of coolant / airflow / btu experiment, this could be VERY difficult to verify