Great pics Gus. I had my 69 GTO stuck on the shoulder slope of highway 22 south west of calgary in a snowstorm. Looked amazingly like your pic. Reminds me of why I moved to Pender Island, February 1989, 90 degrees F difference in temp from the prairies to Victoria.
My electric fans make a heck of lot of noise and irritates me all to H.. The car had the rad, fans and shroud in when I bought it so I just left them there. Getting 200+ degrees one day due to the temp switch in the crossover failing, causing the fans not to ground and thus not turn on was reason enough to hate any aftermarket changes in the cooling system. Took me an hour to scrounge up some speaker wire from a guy passing by in order to ground the fans and get the car home.
If, I didn't have the electric fans and if, I had an over-heating issue I would try the flex fan. I think the stock fan on a stock engine should be enough to keep the temp where they belong. but like Bob says, factory equipment is for factory engines.
I'm not in agreement with the thought that slowing the flow of water through the rad will cool it more. That's why we try to get the divider plate as close to the impeller in the pump, to move the fluid. These are closed systems, once the coolant heats up enough to expel the air out or push the excess coolant into the recovery can, if installed, it should be all coolant and pressurised. Since it is a closed, sealed system there is always a full radiator and as long as the air passing through the radiator is cooler than the fluid in the radiator, heat will exchange. The rad must be full with no air to operate at peak efficiency, that's why some people put recovery cans in their system. Energy, heat, will transfer from the coolant to the air. It's not like waving ones fingers through the flame of a candle and not burning them. If slowing the flow in the radiator would cool the water more then slowing the flow in the engine would heat the water more in the water jacket.
The unfortunate thing about the way the heat exchanger system is set up is the vast amount of heated air that is propelled through the rad, over the hot engine and all around the cockpit of the car. That and the extremely hot headers can get the temps in the car to an unbearable state. But for the most part it works, my interior overheats while the engine coolant is 190F.