I did a quik sketck on paper with both ideas .I also drew arrows to show the way the water flows .
By changing it around will result in over heating or create a hot spot .
the pump is also directional and is there to create flow not pressure so pumping water to the bottom may not happen.
also most water cooled engines are designed to send cold water to the bottom of the engine as heat rises to the top ...............
EDIT sorry daveman went for coffee comeback well explained

that was the only problem that i could think of and it sound dead right cheers daveman

do you mean plumb the top thermostat housing outlet into the bottom of the radiator and vice versa?

Not a good idea. You will have issues with thermo siphoning. Hot water will be entering the bottom of the radiator and will want to rise straight to the top as it's less dense the the cooler water in the radiator. The motor will then be sucking in hot water from the top of the radiator. It wouldn't be as black and white as that but you would find that there would be cold pockets forming in the bottom of the radiator.

In regular radiators, the water is pumped from top to bottom but the water also has the tendency to fall to the bottom as it cools anyway so the water entering the motor is the coolest available in the radiator.

i meant in the opposite direction you get the picture anyway

Doesn't it flow top to bottom normally?

does anyone know if you were to connect the radiator piping so it flows top to bottom instead of bottom to top would it affect the temp? i dont see why it would