Hi Boot, on my boat the water inlet hose is tapped into the crossover, this is were I installed the pressure relief valves. This way the intercoolers do not have any flow until the block pressure rises.(at about 2500-300rpm`s)
Man, what a difference now I can idle at no wake speed all day and I have not changed plugs since May, when this was done.
I bought the valves from PFM Superchillers but all they actually are is a 1/2"pipe Watts pressure valve.
Good luck, Kurt.