Heater core replacement. Are they all the same from all vendors? Where to buy?

[Robert Bare]

Copper dissipates heat almost twice as fast as aluminum.
That's why it's used for soldering irons.

Yes, but there are other factors involved. Copper rads and heater cores have more mass, retaining more heat. Aluminum rads and heater cores have better air flow, and better coolant flow.
I remember when aluminum radiators first came out, nay sayers were abundant. So, VW but a VW Rabbit rad. in a big block vette(with a/c) paid people to drive it across the country, and all around. Never had an issue, and ran much cooler. Also, ask anyone with a early 90's 454 C/K, that finally gave up with running hot problems, and went to a aluminum rad.

 

[Grit dog]

Bottom line ANY new heater core will put out enough heat to drive across Minnesooota in January at 20 below zero. It’s simply not an issue of heat output of brass vs aluminum.