Do the newer magnum style thermostats flow enough

11.2 said

I think I have a water flow issue, I'm running a 180 thermostat but my lowest temp I see is 195. This is with a clutch fan down the highway on very cool days. if the system was working properly it should be running around 180.

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This last sentence is ONLY true IF the rad and cooling system has the heat capacity to shed enough heat to get the coolant down to around 180 F. The t'stat does not set the running temp by itself; it only sets the lowest possible running temp. The rad area and airflow across it set the actual running temp; if it that temp is above the t'stat temp, then it will go to the higher temp.

As said, I suspect you do simply do not have enough rad; a 2 row 22" is small for a 416. The heat shedding capacity of the rad simply is not enough, and the cooling system heat capacity equals the cruise heat production of the engine at 195. To get this down, you need more rad or air flow over the rad.

BTW, I would not test with no t'stat as it will lower the pressure in the heads and block and may get hotter due to the subsequent localized boiling. Part of the function of the t'stat is to BE a restriction and thus increase the coolant pressure in the heads and block. If you want to do this test, then gut a t'stat and put the outer piece in as a restriction.

BTW#2 195 is not a bad place to be....