Electric VS standard fan
The lack of a shroud is a big issue. The fan alone may move a lot of air but since air is like water and electricity, it takes the path of least resistance.
It will pull the air from around the radiator easier than thru it, which means that airflow thru the rad is much lower. That is why a tight fitting shroud is beneficial. All Mopar A/C cars came with them....air flow thru the condenser.
My 73 340 has factory A/C with the 26 in. rad and shroud and it will stay cool all the time.
Little bit of history.. LA County is one of the first police agencies to test cop cars before they solicited bids on new units. Guess what one of the tests was?
The scenario is a high speed pursuit in 100 deg. where the perp bails out out and fllees. Cops chase him on foot, leaving car running.
The set up was to flog the crap out of the car in a simulated chase and then nose it up to a wall and get out of the car and walk away. The car was left in drive with the A/C on and idling for a while. They had temp probes on key points of the car, brakes, rad., trans, rear end, interior etc.
The car better not flunk this test.
Shrouds are installed for a reason.