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Discussion Starter #1
I'm in need of a new radiator for the 68 and have pretty much settled on using an Ebay aluminum radiator.
While the bigger is better mentality says go with a 4 row,I'd like some input on my choices which are:
Two 1" cores
Three 3/4" cores
Four 5/8 " cores
As long as the airflow across each radiator is adequate, will the 4 row have the most cooling capacity,or do the wider cores of the smaller radiators provide some advantage?
 

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volume of coolant , suface area , air flow cfm thru the core .
The one with the most is the winner
Ditto. The wider big block version (24") will give more cooling than a small-block version that's thicker. Thickness and extra rows benefits rapidly diminish through air heating and stagnation, so don't be tempted to go thicker. Just like small-tube brass/copper 4-row cores don't cool any better than 3-row cores. Area and flow, and don't get your panties in a bunch trying to decide - all of your listed choices will cool your combination with lots of capacity to spare. My personal choice for similar combo's? Generic racing 2-row, 1" tubes, louvered fins, 24" core, shrouded clutch mechanical fan. Electric will do OK with the excess capacity.

David
 

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Much the same thinking here in my 63 F;lane, a stock 68 F;lane rad using a wider bottom tank from GDI industries so the shop could wedge an off the shelf 3 row into it, the top tank worked fine, Mark V11 Electric fan with Varible Speed controller by Flexalite & my only problem was getting it up to running temperature,(347c.i.-420+hp)
A great bargain to boot.
 

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Discussion Starter #8
Thanks to all for the replies... they are very reassuring and helpful.

My current radiator is a 20" wide 4 row brass with a 16" electric fan. It has been adequate to this point,except in the hottest times in the summer.It doesn't overheat,but will get over 200* after a substained cruise. It has a couple of leaks in it now,and I would prefer to upgrade than repair it.

All the ones I mentioned are 24" cores,and the 3 row Champion is in fact what I was leaning toward. I will probably get an late model electric fan and shroud assembly from the local Pullapart.

Frdnut I have already viewed your article several times this week lol. The advantage of the cross flow design had me considering a similar route,but I don't want to part with my passengers side inlet/outlet radiator hoses.
 

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If you can find a single row with a high fin-per-inch count, it'll usually be more efficient than a two row with less fins/inch. When the tubes are installed, some radiators have them staggered which somewhat helps air to flow but it still restricts. The more fins/inch the better.

Our fork lifts at work I think have about 2 fins per inch and 3 rows...looks like an old 9N Ford tractor radiator. And they don't work worth a crap either. Overheats every time the outside air temp is more than 25 degrees F. One of them we replaced the factory radiator with an aluminum tractor radiator (out of a Kubota and it halfway fit)...it has a LOT more fins. Now that lift works absolutely perfect. Thermostat opens and closes and we can see it on the temp gauge...but that's as warm as it gets even in the summer heat (112-117 last summer)
 

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I'm running an aluminum 1" tube two row cross flow generic from Jegs. It is their smallest one (22" x 19") to fit the stock opening on my Falcon. It was right around $160 to my door. I had a custom shroud built and use a stainless flex fan for simplicity.

The car never gets over 180 and usually runs around 165-170 at any speed or dead stopped idling at any outside temp (over 100 degrees many times). :D

John

PS: My motor is making around 450 HP.
 

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Typically brass radiators actually reject heat more effectively per core area, but they are heavy and hard to make big. Tubes have to be made thicker to support their own weight, and that cuts heat rejection too, so it's more likely a larger radiator will be aluminum.

Fin density is key - core thickness much past 1 5/8 is pretty ineffective with a standard fan - the thicker the radiator the harder it is for air to flow through it. Make it thick enough, and the air reaches stagnation and just goes around the rad/grille entirely. Plus you lose effectiveness - the hotter the air gets within the radiator, the less it rejects as it goes along the flow path, so exponentially diminishing returns

More core area increases heat rejection with a linear relationship - more square inches, proportionally more heat rejection. Fit the biggest core you can get and go with the 2 or 3 row. Anything more is a waste.
 
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