The biggest two core aluminum radiator you can find. The cores should be 1.00 inch minimum and 1.25 is better. You can’t get much bigger than that on the tubes because the radiator gets so thick it restricts air flow. Ignore the copper/brass cools better because it doesn’t in a correctly sized and built radiator. 4 small tubes don’t flow as well or cool as good as 2 big tubes. You can’t use big tubes with a copper/brass radiator because the materiel isn’t strong enough if you make the tubes that big.