[bobcowan]

The water temp sender should be at the front of the engine. The coolant flows through the block, and cools the cylinders. Then it goes up into the heads, and foreword to the thermostat, and then (of course) to the radiator. If you put the gauge sender in the back of the block, it will only read the coolant temp as it leaves the block, not as it leaves the head. It won't provide you with usable information.