Two 1 inch cores will flow more than 3 half inch cores.
You need more coolant flow.
Look at an aftermarket water pump. Dont know what you have but I would see if Milodon makes something. Or Flowkooler, but Ive never used a FK.
I can tell you that its a PITA to get a good radiator any more. Marketing says MORE CORES but engineering says fewer cores with a bigger diameter. When I was young, a long time ago, all the chevy guys had 4 core radiators. Almost all of them ran hot. My stock 2 core 26 inch radiator would out cool them all day long.
My goal is to not use a fan and still control heat. Time will tell if I can.
