I have had multiple rads and fans in this car. Current is the big 2 core Copper Brass rad with Dodge Stratus fans on low. It never went above 195 in my 70 Cutlass, usually 170-180, no shroud and 4 blade fixed fan. The main issue is the highway temperature, should never go 215 with a 260. The 3 core Champion was so so at best with the 403, 185 with a 160 Robert Shaw thermostat, 230+ towing, even after dumping the underdrive pulleys. The no name aluminum 2 core with 1" tubes did well till the Mr Gasket no flow err I mean high flow thermostat started acting up a very short time in. Then it started leaking between thr cores, stop leak killed it's cooling was 235 after a short drive with 9.6 to 1 Olds 350. I agree on the large 2 core with 1" tubes or bigger being the best. I also tried a 5 and 7 blade fan with a new clutch and shroud. Been there and tried nearly everything.