Ok, once again a simple question has evolved into a ?? contest. HMM OK let me add my 30+ years of engineering experience to this. No offense meant to the intelligent well informed responses.
In my career I found that water soaked 2x4;s and water logged sheetrock outperformed Brass and Aluminum as long as the car was submerged in straight water. Now, I do have to admit that adding Salt to the water or Ethylene Glycol had an impact on my results.
I Hope someone enjoys the humor in this post,

And aluminum radiators should be dirt cheap due to the quantity of empty Bud Light cans available !!

I'm sorry I guess everyone should make their car the way you want it so you can say it was done right.

My personal experience on the copper/brass vs. aluminum radiators. My 68 Dart GTS, hot 360. I fought a cooling issue for a short length of time. Had a later model A-body radiator, shroud, fan. etc. Everything but the shroud was new, all hoses, water pump, thermostat, radiator, belts, engine was fresh built, fan was new as well. It would consistently run 220 plus and sometimes higher. I actually replaced almost every part on this thing with zero improvement. I tried different fans, water pumps, t-stats, hoses, even another new radiator. Never a single change. Even added a new electric fan added to the front of the radiators. Everything ran the same. Finally, after reading how aluminum dissipates heat faster and more efficient than copper/brass I bought a new one. I even bought one of those cheap units from Ebag. I had to fab up some brackets to mount it. And this was without any kind of fan shroud. I put it in, filled full of collant and I barely ran over 160 again. It could be 90*+ outside and the highest I ever saw it was 170*. I've had the very same experience with my 79 Dodge dually. Had a NEW copper/brass, couldn't keep it cool in the summer with the a/c on. All I did was buy a new aluminum radiator and all cooling issues were gone. This is my personal experience. I will always disagree that a copper/brass is better for cooling.

I worked in a old timey radiator shop in my youth. Your original A-body radiator probably needed riding out as the tubes plug up over time. You wouldn't believe how many old tubes were probably plugged solid... So its likely a new brass radiator would have fixed your cooling problem as well....unless you are saying the radiator was new too? Were they the same capacity/configuration radiator?

Yes, 2 new copper/brass radiators, neither would cool. Aluminum took care of it right away!

Ram charger 4x4 360, 0.30, 9.2:1 compression, stock heads, aluminum intake. Stock radiator 160 thermostat summer time it would over heat on long uphill pulls so I swapped it out for an aluminum perfect fit 2 core which fit near perfect. The width heidth and thickness of radiators are near identical. The aluminum radiatordropped temp two gauge notches. Winter comes along and pow 35 degree days and I get 65 degree heater temps that wont do. I pull thermostate, install 195 thermostats, it runs 1 more notch up the gauge and heater temp is in the 85 degree range. Thinking of going 210 thermostate.
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Silver is the best heat conductor followed by copper a close second and aluminum a distant third. But radiators are not made from copper Too soft. So radiators are made from brass a combo of copper and zinc "brass" is half as good as aluminum at conducting heat.
WELL that came from Richard Ehrenburg, SAE that's good enough for me as I have not been steered wrong by his advice tech or articles.

The plot thickens

I had a Ramcharger in the past...

Older truck, 360 also...

OEM cooling config worked fine...


Something else in the mix...

What would the fix be in the past???

Pre-aluminum rad availability...



Been in bumper to bumper, 95+ heat, multiple occasions...

Sometimes for hours at a time...


OEM 'air' system...

20 years of running time...

26" rad, A/C water pump, viscous, 7-blade fan, shroud...

NEVER have seen the temp beyond 180...

G
No, hot one has a Merzzery or however you spell it. I'm saying that's the problem, do you agree?

I agree...I ran my 500+HP Street Car on long road trips over mountains even in summer with a stock water pump and electric fan with zero issues (180-190 degrees +/-). I changed to a 55 GPM water pump and now the cars temp creeps up to 220 +/- even driving around town in dead of summer. I'm going back to the stock water pump...

There are way too many variables involved to answer the question here with anything other than ones opinion, PERIOD!!!

It is not just the material, a few of the other variables are,
Fin Count, number of rows, are they staggered or not, are the fins louvered, thickness of the fins, how many fins per inch, how are the fins attached to the tubes, diameter of tubes, thickness of the tube walls, spacing between the tubes and on it goes.

I'd go with a direct replacement brass unit, you know it will work for years and look proper in your car (not to mention fit correctly without cussing}

I think to many people on here arguing about this subject think that a brass and copper radaitor has brass as part of the liquid cooling system, which it does not. The tubes and tanks are copper and the brass is the thin strips wedged between the tubes to suck heat out of the copper tubes into the air If aluminum radaitors weren't cheaper than copper radaitors are now do you think the car companys would use the aluminum in spite of the costs The aluminum radaitors are cheaper, not better

cab, i hate to disagree with you, as you are a super and respected source of information, but most tanks i have seen in the 50 years i have been playing with cars have been brass. this is especially apparent when the tanks are stripped of paint and polished. just my experience. or are my eyeballs that bad ?

To the OP:

Whatever radiator you choose to run, make sure to do a thorough flush out job of your cooling system before installing the new unit. I would even go so far as to advise flushing out the block by removing the drain-cock or a freeze plug and spraying your garden hose in it for a few minutes until the water runs out clean.

Get all the nasty stuff out that will plug up your new unit.

good point there. I usually end up putting radiator petcocks in place of the block drain plugs to easy future draining. You'll probably find the hole plugged with stuff and will need to poke it loose once you get he block drain plugs pulled.

I have used these for 30 or more years for a very fast and quite good reverse flush. Certainly beats crawling under the car to open jammed up block and radiator petcocks,,or worse yet removing bolt in plugs from the block.

You need not have it installed permanently if for cosmetic purposes,,,just tap unit in before flushing and remove when done. Also flushes out heater which simple draining does not.

I also leave engine idling while flushing. Flush until coolant runs clear out of top of radiator. Always keep water flowing from hose while engine running as otherwise you can damage water pump from lack of lubrication that coolant provides.

Some 15 minutes for whole job. Your cooling system will love you, therefore it will treat you well.

http://www.amazon.com/Prestone-AF-KIT-Flush-Fill-Kit/dp/B000CCFY5W

You don't put drains in the block for flushing, you put them in there to DRAIN the block. You know, get all the coolant/water out of the block. So you don't drool coolant all over the place when you pull a head or something similar. Pretty sure the Prestone flushing kit doesn't get the sediment at the bottom of the water jackets out either. Since I've seen it come out my drains after a flush, draining all the water out for a proper refill.

Aluminum conducts heat twice as fast but needs to be twice as thick so it is a wash. The real issue for functionality between the two is the vast difference in mechanical desighn NOT the material. The OEMs do it in AL because it is cheaper, they also use those stupid plastic tanks on the end because they are cheaper but usually around 5-10 years old they start leaking and need replaced, especially with dex-cool type crap coolant. Many brass radiators (includeing brass tanks) are still in service 50+ years later .