Higher coolant flow will ALWAYS result in higher heat transfer. Coolant cannot absorb heat after it reaches it’s pressure corrected vapor point. Furthermore, coolant absorbs heat at a progressively slower rate as it approaches this point
My experience is 99.999% of heating problems are air flow problems. Nothing beats factory fans, be them mechanical or electric. These Mark VIII/GT-bird, etc., type Ford fans mentioned a couple times above, are the only electrics I will use. Perfectly sized to cover most pre-war type radiators, built in shroud and move plenty of air. Bonus, they are two speed fans so if you want to get fancy, can add that feature to your car. You can tell just by looking at the blades of most aftermarket fans that they are likely marginal air movers.
Thanks for everyone's input. I have been running a six bladed mechanical fan but without a shroud. I think before I go with the electric fan, I will get a shroud put on and see how much difference that makes.
Delta Pag makes one of the best electric fans you can get. 3 speeds and can be programed with their controller. They are pricey. Some of the heavy hitters that run drag week in their 6 second cars use them. Very nice set up, but not cheap. Right now and for years I have a Spal pusher on the drag coupe. Works very well.
I run a Spal on my car, 16" and I forget the CFM. I looked on Summit, they wanted extra for everything else, eBay to the rescue. I got a kit with the fan, relay, mounting stuff for maybe $15 more than Summit wanted for the fan itself.
The added benefit of an engine driven fan is that you don't have to listen to that electric high speed wine at a stop, or just idling down the road at a show.
Mine will come on if I'm idling in traffic, really not annoying. It will run until it cools down, rinse repeat.
I've used a Cooling Components electric fan and their shroud with a Walker Radiator on two cars. 'Wired the fan to a switch in the cockpit and only turn it on when needed in traffic or sitting, runing for long periods. Never had a problem and one of the cars was driven cross country. Walker Radiator, as you probably know, is now owned by Johnson's in AL. Given Johnson's reputation I'd assume the quality is still there. Simple, easy and it works.
The results of an independent air flow meter test likely won't make sense unless you test in the same conditions in which the manufacturer rated their fan CFM. Those conditions don't seem to be readily available. Your own air flow meter test is likely more applicable as a comparison between fans in a set application to see what pulls the most CFM rather than trying to see if the fan matches its manufacturer CFM rating.