I certainly agree that radiator performance is much more responsive to air flow than water flow. Without going into heat transfer theory, it's because of the difference in specific heats of air (.24) and water (1.0, or .85 for 50/50 antifreeze).  However, if the water velocity through the tubes drops below a certain level, radiator performance will quickly degrade.  This is based on my experience as a "cooling systems engineer" years ago and also from some data I have from radiator manufacturers.  The following data for a specific radiator shows the relative performance of a given radiator when varying tube velocity. The baseline is 100% at 100 feet/min tube velocity.

(tube velocity, feet/min), (performance, %);  (200), (105%),     (150), (102%),     (100), (100%),      (60), (97%),    (40), (95%),    (30), (92%),    (15), (84%),    (10), (80%),    (8), (75%),    (5), (65%)

As you can see, increasing or decreasing the water tube velocity from 100 feet/min has little effect on radiator performance.  However, when tube velocity drops below 30 feet/min radiator performance starts dropping significantly. This could be an important issue for radiator performance at idle when water tube velocity is at a minimum. At 5 feet/min tube velocity, radiator performance is only 65% of what it would be for 100 feet/min.  For less than 5 feet/min, performance drops to 0 quickly.

Bill Newland

US Radiator in Vernon Ca. is who made the one for me. I had a 3 row and I stayed with 3 but with a lot more fin area. I also had them add a AT cooler in the bottom in case I change transmissions. Great folks to work with...

56 Vic, B'Ville 200 MPH Club Member, So Cal.

Go on line and look at US Radiator they make an exact model with all kinds of fin and tube options. Should be all you need and more.

What comes to mind, is it boiling and are you using the factory gauge as an indicator? A lot of movement on a factory gauge might only be a small rise in temp and if it is not boiling then there is less to worry about. The only way to be sure of what is happening is with a quality gauge that is properly calibrated. My factory gauge has gone all the way over to the last mark when it is over 100deg stopped in traffic and the car has not boiled with a 13lb cap. I always check the release pressure on the cap to make sure they are working correctly.

one last thought is 200 is not over heating,with a good rad and presure cap210at a stop sign is not going to hirt the engine,with air cond i would always shift to nat a light.

I agree, if enough coolant is moving through to begin with, then a smaller pulley will do no good, and the problem lies elsewhere.  With that huge pulley, it just isn't moving fast enough, as observed by myself and others.

Miker also brought up a good point, and that is when it occurs.  If it is not at idle, then a pulley change will not fix it because when you're cruising down the road, a fan is not even needed and the pump speed is more than adequate.

Myself, I had an issue at idle.  When I drag race, I increase the idle speed to 1000rpm, which helps me to leave more consistently.  I never experienced the problem while idling at that rpm in the staging lanes.  I swapped to a smaller pulley, and the problem seems to be solved at normal idle speed, in normal traffic situations.



Lawrenceville, GA

Every thing you need to know to" KEEP YOUR COOL"
This contains FACT as opposed to educated guesses.http://teae.org/cooling-the-sunbeam-tiger-tiger-tom-chuck-king/
Pete

Meteor... I'll go along with everything you said but it just didn't work for me. We had a 55 and a 56 new and never had a heat problem. But waiting at a 2-4 minute stop light in mine the guage would go to 200+ it was nerve racking. Putting in nuetral and razing the idle was the only way to help. After discussing this with Greenbird on this site he told me to start the car with the rad cap off and watch water flow after reached temp. There was never, ever movement of water at idle. A slight raise in idle, like 200 rpm, and water moved. I'm an in town driver and rarely go on a hyway or freeway. I did the smaller pulley it worked. I believe Ted came on later in the thread and said Ford had 6 or 7 different diameter pulleys and I believe it. A Minnesota car could have had a different one than an AC equipped car in Arizona. I feel I wasted money on a radiator that had more fins for extra cooling that just prolonged the heat up. And for the restricted hole in the bypass it only makes sense. Even with an open thermostat a 7/16" hole recirculates a lot of already hot water.
Every thing you stated is true and I agree with and I even found the upper rad mount to hood seal to force more air threw the rad but it just didn't help mine... Some also blame the s--tty gasoline and could have something to do with it too......

56 Vic, B'Ville 200 MPH Club Member, So Cal.

why not recore existing rad,then make sure all the shrouding is replaced,like the rubber between rad and upper rad aria,fan shroud is a must,with 2/3s of the fan in the shroud.I do not think spinning the water pump faster will accomplish aney thing.water going threw the cores quicker serves no good, main criteria is all the air posible goes threw the cores. limiting bypass is a fallacy,and will cause cavitation .tbirds have a less efficient water pump due to the spacer. all other applications have no need to increase wpump speed.if running air cond. on a 55 0r 56 car i would suggest a recore with the extra cooling needs. googal how cooling systems work and you can then make a informed decision. there  is a lot of witch craft out there. my info comes from teck school and courses from caterpillar. whew had there share of cooling isues.

we had our hotest summer last year,had no isues with my 57 ranchero,which the rad is far from perfect,but shrouding is like new. good luck

I had similar issue on my '55, but it does not have A/C.  Temps would rise on hot days and especially if stopping for more than a minute or so.  Switched to an aluminum radiator and to a 6 blade fan and the problem is much reduced.  Since you have the electric fan you have already addressed part of it.  I had already put the reducer in the bypass hose with no improvement.