I believe that the aluminum radiators are more efficient than brass.

I replaced a 3 core brass radiator on a 65 mustang with a 2 core aluminum. The guy had installed the 3 core 2 months earlier but it was unable to keep it cool. The motor was a near stock 289 and once the aluminum radiator was install no more problems...

Question... If brass radiators were better...Why did auto manufacturers switch to aluminum? Just a thought.

Steve