Hey man was reading about your airflow through the radiator. I deal with cooling problems all the time in Texas and the best system that I have found is an aggressive pitch mechanical fan and a proper fan shroud. It may rob a little horsepower, but it will pull massive amounts of air. Hope this helps.

1968 F250 longbed 2wd.
Late model 351w c6 trans.
1969 F100 Explorer
360 3spd manual
1967 Fairlane wagon
302 c4 trans