Aluminum better than Copper Radiators ???
Except for weight, it’s not exactly so with modern copper construction.
(Weight is what lets me pull some big dog out of a pond with my "Little Car")
Here is some analysis from various internet sites –

In determining the appropriate metal for car and truck radiators, an important criterion in recent years has been relative weight. Because of its low density, aluminum has grown in popularity for this purpose despite its inherent weaknesses in thermal conductivity, corrosion resistance and repairability.

Particularly impressive is the fact that a copper/brass radiator core is far more energy efficient than an aluminum radiator core of equal weight (336 KWh vs.426 kWh).

When you combine copper/brass's superior thermal conductivity, corrosion resistance and strength with it's highly favorable life-cycle energy use, virtual 100% recyclability, and exceptionally low energy cost as remanufactured scrap, it becomes clear that the world's oldest known metal will be even better for tomorrow's car and truck radiators.

And this –
The recent history of the passenger car radiator is well known - the conventional wisdom is that aluminum has largely taken this market. The trend started in Western Europe, has moved forward in the United States and has more recently taken hold with Japanese automobile producers. But aluminum penetration in the large aftermarket is only about 10%

But the copper/brass radiator was too heavy - not because the laws of physics dictated that it be, but because no effort to improve design to take advantage of superior mechanical properties and thermal conductivity had been expended. More recently, in tests conducted at Penn State University on three generations of the new brazed copper/brass radiator, CuproBraze radiators were shown to be fully competitive with the brazed aluminum.
These data are shown in the table below.
Table 4.
CuproBraze vs. Brazed Aluminum
Radiator Core: Brazed Aluminum CuproBraze I* CuproBraze II* CuproBraze III*
CoolantPressure Drop, kPa
4.75 3.31 2.89 4.75
Air Pressure Drop, kPa
0.307 0.216 0.307 0.307

CuproBrazeI, designed to have the same frontal area as the aluminum radiator, has 30% lower air pressure drop but is slightly heavier.
CuproBrazeII has the same air pressure as the brazed aluminum model, but is smaller in size.
CuproBrazeIII combines a smaller frontal area and thinner tube walls to achieve distinct advantages in both size and weight.
All four of these radiator cores have the same cooling capacity (168,000 BTU/hr) and fin depth. Their weights include fin and tube material only. This work has shown conclusively that a much lighter copper/brass radiator is possible. In addition to replacing the lead solder by a brazed joining system, tube touching design and compact core designs were among a number of innovations that reduced the weight of the copper/brass system.

And this from the Sunbeam Tiger page–
Aluminum conducts heat about 1/3 better than brass. However, copper conducts heat about twice as good as aluminum. Then again, the brass/copper is held together with solder which conducts heat poorly at a rate about 1/5 as good as aluminum. If aluminum radiators had to use the same design dimensions as brass/copper radiators, aluminum radiators would be less efficient than brass/copper radiators.
NEW DESIGNS USE LEADLESS BRAZING.

From chevyhighperformance.com –
Many new performance radiators, such as those
from Griffin and Be Cool, are made from
aluminum that offers weight savings over
copper-brass. While aluminum does not
dissipate heat as well as copper-brass, modern
radiator design more than makes up for the
difference

Look here for a test. –
http://www.usradiator.com/testing.htm

Roy