It’s NOT just about flow. It’s about surface area too. If you look at the thermodynamic equations that govern heat transfer, the two biggest components are surface area and flow.
So no, you can’t just say bigger tubes and fewer rows are always better. That’s 100% not true.
It’s a balance between flow and surface area. The Champion 3 row radiator, with .75” tubes, cools my .060” over all iron 340 pushing 400+ hp just fine. And I drive it all summer in temps as high as 110* F. Giant tubes are just as much of an advertising gimmick as adding more and more rows. You don’t need (or want) a 4 row radiator, just like you probably don’t need or want a 2 row with 1.5” or bigger tubes. Anybody that says different is trying to sell you something. And probably never had any education in thermodynamics.
Between a 3 row with .75" tubes and a 2 row with 1" or 1.25" tubes the cooling numbers would come down the specific manufacturing details of that radiator. But I've seen both work just fine in an A-body, so unless you have more than the published information saying one is better than the other is just personal bias.
