jeclutterbuck

by how much will the coolant (50/50 fresh water/antifreeze) temperature increase when it is already 180F flowing into the manifold thru a 1/2" ID hose?

the coolant will flow out of the back of the block thru 1/2" NPT fittings, into the base of the manifolds, then out of the top (dry joint) and into 2 (each manifold has it's own, 1 traditionally used for bypass, the other for the heater core in an automotive application) 1/2" auxillary coolant-intake ports on the waterpump. when the water reaches 180F, the thermostat will open flushing the block water to the heat exchanger, but the manifold coolant will always come out of the block and return directly to the pump. my concern is; will i over-heat the coolant? i figure this could be an elegant way of keeping the block at 180 and prevent cold shock as the heated water from the manifolds would mix with the cooled water coming from the exchanger. also, is 1/2" ID hose too small? assume an aftermarket water pump.

thanks!

volvo penta outdrive pivot housing is cruddy looking, so i'm going to have it blasted and re-coated... i was wondering if powder coating would be better than having it painted like it came from the factory... i've had a couple of people say to have it painted rather than powder coated but i don't know why...