Post #8.
Yes, copper has better thermal conductivity than alum; but the larger tubes that can be used with alum allows for much more efficient heat-shedding fin design, so the alum rad cools better.
Sounds like you could do all of that with copper as well. Bigger tubes, fin design..
You're beginning to sound like one of the American Cruising Inc crowd that used to hang around that service station on Mona Vale..
