the people that think slowing the water flow thru the radiator cools it better are forgetting that slowing the water thru the radiator also slows it thru the block thereby picking up more heat, if your theory was true then it's a wash.

Thermodynamics does not work like that.

The biggest factor in heat transfer efficiency is temperature differential, not time.

Your analogy of a bigger pot vs a smaller pot fails because unless you are heating the same amount of mass it's not a valid comparison.