Ken,
I injected the water in front of the carb. I built a small nozzle into the airfilter housing that was bent 90 degrees and sprayed through the carb directly at the compressor blades. I've not had it apart in all these years, so I'm unaware of any problem with what I did.
If that was a problem, one could avoid it by using a pressure capable water bottle[like a surge tank], and run a line from the intake[power brake tap] to the top of the bottle to help reduce the pressure the pump would need to produce to overcome from manifold pressure. The pressure line for the pump would come off the bottom of the tank to wherever you wanted to introduce the water. I believe there are aftermarket washer pumps. I've seen surge tanks with top and bottom outlets and sight hoses on the sides in Streetrodder outlets.
