you've answered your own question right there. Every vehicle, with any engine combo should be able to completley remove all cooling fans and be able to drive above 45 mph and have zero cooling issues. this is due to the forced air being pushed through the radiator.
On my v8 swap i had a climbing temp issue above 65mph. I had the V6 rad and the intrepid fans. II removed the interepid fans and went for a blast down my local highway. What i ended up finding is i had an air pocket underneath my engine bay where the hot air leaving the rad would turn and go back into the radiator. I brought a few pieces of carboard and sheetmetal with me and put various 'airducts' taped to my truck under the bumper and on the sides of the rad until i found the issue. I could then drive from 55 to 105mph without any issues.
GM has put air dams under vehicles for a while. 3rd gen camaros (think KITT) have a very necessary air dam under the core support that if not there, will over heat. Just that one simple piece causes that much issues. thats where i got the idea for the duct work under my truck .
Also, all the red arrow hot airs are just going right past your rad..
remove the pusher fan its not needed.
check your puller fan specs, they might not be good fans.
make sure the fans are sealed to the rad
and block off or redirect all air (red arrors) that are escaping around the rad. youcan easily bed a piece of sheetmetal and direct the air through the bumper towards the radiator
