I encountered the opposite situation on a 63 Chevy II that the auto body shop instructor at the high school where I worked had restored. The car would run OK at low speed, and overheat on the highway. I discovered he had installed a fan blade from a Chevy Vega, which had a counter-rotating fan. At highway speed, the pusher fan would stop airflow through the radiator, but it would push air through it at around-town speeds.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!