I would run a e-vac system on the headers. you should not get any water until 2000 rpms then only a mist. but why are you running water to the headers? coat the headers and run them dry then you don't have to worry about the water. if water is the way you want to go I would run a line off the t-stat housing through a small ball valve then through the basset t-valve also use that to Y off and go to the headers. do not cut the basset spring use the valve to control the amount of water going to the headers. in doing this you need to be sure that the motor also has another exit off the t-stat housing that is going straight over board no valves. I ran this stystem for 6 years on a flat then went to dry headers. never got any water in the oil. remeber 2000 RPM's. If you are trying to flush the water out of the oil, mix 75%diesle 25%oil turn motor over with starting it to build oil pressure then drain back out repeat until motor is clean. or just pull it down and wipe all parts down. good luck