Friends:
I never really understood all of these over heating problems with these flat head engines, The part I do not understand is why it is so hard to solve. Granted I am not a specialist in the field of water pumps but as a plumbing contractor who also installs home heating systems I have a good knowledge both practical and theoretical dynamics of the principles of btu transfer.
I will say that I do not have a flathead in my trucks engine bay, I have a 351 stroked out to a 408, it makes a lot more heat than a flat head and it sends that heat to an aluminum radiator. Truthfully I think the radiator could be a copper core and would still be able to cool this engine which I believe generates a higher BTU out put than a flathead does, I therefore do not believe the cooling problem is in the radiators unless you are using a junk radiator that is limiting BTU transfer due to corrosion blockage.
Do the number of fan blades on a pump matter? Not really, the shape contour and RPM at which those blades rotate are going to determine the efficiency of that pump, therefore a pump that has 4 veins, 6 veins or 8 veins should not be considered better or worse than each other without direct engineered application trials. In a restricted system an 8 blade impeller may cause cavitation or pressure bubbles that actually would cause it to be less efficient than a 6 or a 4 vein impeller.
It would be in the best interest of the science of the process to determine where the design flaw exists on these flathead engines. Is it an internal casting flaw? Is it a flow problem occurring as the coolant is being circulated? Is it a flow capacity issue, an operating pressure issue, a fan RPM issue/air circulation issue? I notice some go 90 degrees hard to the radiator, some go 45 degrees to the radiator in their tubing routing, 45 would be best.
I would say that the root cause of the problem would be low water flow or that the problem could be solved by increased water flow. To achieve this you can route your hosing with sweeps and long radius tubing, use the pump with the best flow characteristics that are test proven not just acclaimed, test the flow characteristics of a variety of pump and vein designs at different rotational speeds through an operating system, redesign the fan assembly to conform to a stock yet accepted specification that is efficient and moves a maximum amount of air through the radiator.
Just because something rolled out of a factory 75 years ago does not mean that you should suffer through its use and keep it bone stock as an ill designed system.
The man who has the engineering expertise, and capacity to produce a well designed comprehensive cooling system for these engines is going to make a tidy penny. The man who can design a comprehensive installment guide that is proven through testing and field use is going to be a hero. My suggestion is that from now on we should work together as a group to define exactly how to cool these engines and share proven tested knowledge and data to achieve that goal instead of claims and counter claims. Science.
Thank you, Frank The Plumber.