'66 Valiant Running Hotter than Expected

Jim Kueneman said
It’s pretty much where I am to Rusty. The duster doesn’t have any problem but recall the duster I actually put a 73 and up radiator support and the big 26 inch radiator. That could be the main reason why that one doesn’t have a problem. This is just a narrow 22 inch radiator, that’s all they did in the early days even with air conditioning I was just hopeful that the aluminum heads and having Bob do a four core would make a difference, but seems like I’m wrong

There's been a lot of studies that show an efficient 2 row radiator with 1" or 1.25" tubes will out cool a four row. The theory is that once you start stacking so many rows in front of each other, they block air flow. I'm no thermodynamics guru, but that sounds very plausible to me.