One can debate about cooling efficiency but..
Mopar designed an adequate cooling system the challenges are when engine modifications are done..
We have found often the cooling problems are related to incorrect ignition timing and/or lean fuel mixture.
IMHO.. Today it is difficult to find an experienced mechanic that will take the time to diagnose and correct that doesn't cost major $$...

Just my $0.02...

You don't typically get to pick both tube size AND material. Larger tubes are almost always aluminum (stronger material), while the smaller tubes are typically the copper/brass. Aside from just comparing tube size, you need to look at tube spacing and number of tubes. At the end of the day, you can get a lot of heat to the radiator, but if the airflow isn't there, the heat doesn't come out (More tubes and less fin = more pressure drop on the air side for the fan to overcome).

Pick a product from a proven, quality supplier (Glen Ray, Griffin, etc) and you'll be fine. It all comes down to the look you want in the car too.

And don't forget camshaft selection.

Excellent point. "back in the day" it was very rare to find a Mopar performance car (or most any other brand performance or standard car) that had over heating issues in standard trim. They all knew about heat and thermal issues down to having power steering coolers, and transmission cooling etc., They were always on top of those potential issues to the point of even being on the over cautious point.

The other point is...
Today frequently guys will start bolting on these aftermarket electric fans schemes to address their overheating problems..
But..
Next then they fail to understand about the high current drains of the fans, often exceeding what their alternator and wiring can support..


Just my $0.02....

Yes, I went through this with the 383 in my 69 GTS. Typical .509 cam, Torker intake, Carter 650, MP electronic ignition on a stock bottom end. Had overheating problems like crazy, threw everything I could on it, radiator, fans, pulley's, shrouds, and it ended up being to lean and too much timing! This was in 1981, so these kinds of things have been going on for decades...

had a frein back in the mid 70's with a warmed over 383 in a 63 Plymouth. Always ran hot. Hid tried all kinds of things to no avail. When he swapped a 440 in he found the root cause. The water pump impeller was laying in the housing
We weere pretty young and didn't think to check for water movement at 2-3k RPM

A few years ago I had a street rod come in the shop with a new engine , trans, radiator etc. and a heating problem. had been to a couple of different places with no success. It had a 90° elbow on the top tank so you could not really see the coolant. A borescope showed little movement of the coolant at 2500 RPM. After checking pulley ratios, the thermostat etc, we found a red shop towel inside the lower radiator hose All was well after removing it

Use a radiator with the two biggest cores you can find. More smaller cores is not better.

Aluminum will cool whatever you can throw at it and weigh and cost less than other matériels.

Use a high flow water pump. The Milodon and Flowkooler pumps are both great and I’ve use both. Last time I looked the Milodon was cheaper than the Flowkooler. The both work equally the same.

Use a Stewart Components high flow thermostat.

Make sure your water pump is turning crank speed at the MINIMUM. If you can get the water pump turning 10-12% faster than the crank it’s even better. Even 6% overdriven is better than 1:1 and never underdrive the water pump.

It’s a system. You can’t neglect one area and expect the best cooling.

If the system is correct, your engine should rarely run hotter than your thermostat rating. In other words, when the cooling system is correct and you decide a 180 thermostat is what you want the engine even on the hottest days should never go above 190 degrees. And that should be at a stop light and as soon as you get rolling the temperature should go back to 180.

In the same example if your temperature is at say…195-200 degrees with a 180 thermostat then your cooling system capacity, coolant flow (which includes fan speed for slow driving conditions) or both are incorrect.

personally, i like to see around a 195 degree temperature.
that keeps contaminates in the crank case boiled off, as well as a tick better as mileage.
if all is well with the coolant system, even 200 doesn't bother me in stop and go traffic on a hot day.
however, your tuneup must be on target, as well as the total cooling system.
these cars when new came with a 185 thermostat, and that means it starts to open at that temperature, usually becoming fully open 10 or 15 degrees hotter.
also, the dash gauges were marked L to H with a line between for a reason. if the needle settled at halfway or a little less and stayed there, we were happy.
we then installed a mechanical temperature gauge and immediately had "overheating" issues because we saw 195-200 degrees, while the factory dash gauge still registered in the middle, or less. some of the factory gauges ran closer to the L position, and we REALLY freaked out when a mechanical gauge said 195 or so.

I think everybody scared the op away after the pissing match or throwing in their $.02 Copper/brass cool better than aluminum but it is used more often. Shouldn't be a factor unless you want 100% stock look. As mentioned a lot of factors go into getting the "correct" cooling. As a rule of thumb compare the original radiator that was used (engine/accessories(AC) etc) and compare it to a replacement. You can use this as guide or use this one.

many, many years ago when replacement 4 core brass/copper radiators were introduced, sometimes they didn't solve cooling issues, and at the time, the consensus was the cores were too close together, not allowing the heat to fully transfer to the surrounding air.
today, i have no experience with one of those [4 cores] that are available, so i don't know if they work better or not.
i mainly get involved with modified vehicles or resto-mod ones, but i like to learn about new ways/things i don't know, or old ways/things i have forgotten about.
if i'm way off base, please correct me when you can !

I much prefer copper/ brass but impossible to find anymore

Things I have learned about performance engines and cooling systems are you need a lot of coolant flow and good clean airflow over the largest rad you can fit in the core support. I drive a Flowkooler pump 1-1 with the crank and an ECP 26" aluminum radiator with great results. https://speedcooling.com/product-category/radiators/mopar-radiators/page/2/

Gus

Can't disagree with the bolded part
But myself I have seen no change with the flow kooler or other similar pumps testing under as close to laboratory conditions as I could get and measuring with thermocouples and digital meters (laboratory grade again)

When I get a radiator done at glenray it is always 10lbs heavier than if I get it recored at a local shop, maybe the metal is thicker. All I know is Bob's stuff works.

those "flow kooler" water pumps are the ones with the "circular" vanes about 1/4" or so high, on a cast circle base ?
i always like to overdrive the pump some, but is there such a thing as being overdriven too much ? there are only so many pulleys to choose from.

Can't disagree with the bolded part
But myself I have seen no change with the flow kooler or other similar pumps testing under as close to laboratory conditions as I could get and measuring with thermocouples and digital meters (laboratory grade again) [/quoteI

I had an issue with scale clogging my rad over and over so I installed a filter in the upper hose and I could actually see the flow difference between the factory pump and a Flowkooler pump. The filter was a good tool to catch the scale from my block. I ended up filling it 3 times now it stays clean.

Gus