Due to the amount of aluminum in the LS1 powerplant it is a very good idea to use distilled water to keep unwanted minerals out of the system. You also want to use as little coolant in the mix as you can because Redline says that the Water Wetter is most effective in higher water content. Water Wetter is a fluid that bonds to the surfaces inside your cooling cavities and makes great contact between metal and water. This moves more heat out of the engine and into the water where it can be cooled. In my area (Seattle) I feel very comfortable with a 25% mix of DexCool.