Just as posted above, the plug in the water pump is the best location because this is the passgae that both heads send the coolant and "blend it" so the thermostat sees the same motor temp from the heads. What I did was install an Isspro EV 270* sweep mechanical gage in the original temp sender location located on the block between the injection pump and head on the drivers side. Then I moved that sender to the water pump location. If you have a Banks turbo you will need a special pipe bushing called a shoulderless bushing. I think it was a 1/2 x 3/4 bushing. Then grind down some of the sender threaded terminal end and add some wire because the original wire length wont reach. Easy and really great temp readings. If you use the large locations in the heads you will see temps about 7 degrees higher.