By the way, we don't run the setup this way on the Dodge engine.... we made things way more complicated by adding a heat exchanger into which the engine coolant is close looped.... we have an electric thermostatically controlled motor/transfer pump that pumps the iced cooling water from the tank to the heat exchanger .... we were of the mindset that controlling the engine temperaturewithin +/- 3degrees is better....because that's what they do in NASCAR.... and to further complicate things, we added a 3rd transfer pump, a small ball valve and a check valve so that, after the engine is shut off, we can leave the electric pumps moving water through the engine and the heat exchanger to keep the cylinder head temperatures from spiking too high....
We also run a similar system on our Vega with a 432 cu. in Big Chief Chevy....but without the after run transfer pump the water tank on the Vega is mounted flatter and is baffled.... it holds 30 Gal of water/ice....and works quite well too.