Water wetter is a great product,i have used it for years in my flathead and never had a problem.I have an aluminum rad and i run 50 8BA in san diego,i use only distilled water and two bottles of water wetter,my temps are perfect and i have never overheated,with that said i have a clean block and my flathead is timed right.I never run anti freeze for two reasons.1.i live in so cal and 2. antifreeze traps heat hence the name.This product also has the anti corrosive elements in it and lubricates water pumps.i love it and have never looked back