One more cooling issue

Are you getting hot sitting or hot when you get up to highway speed? With 410 gears, your rpms are probably pretty high and that absolutely creates some heat. If your shroud is covering the entire surface of the core, you might not be allowing the 60mph air to pass through the radiator. Rather it could be getting trapped by the shroud. If those temps come back down at idle, you probably also have a volume issue. That could be a blockage in the radiator or the radiator just might not be big enough. Dual 1" is decent but there are bigger dual row rads (ours is one of them) that hold a lot more fluid and that could be the difference between running 220 and 190. (it was for me)