Water pump problems

View attachment 36949 Well I am hoping someone on here can help me figure out what is causing this to happen on my 360. This just started happening after I changed the cam and put aluminum heads on, I highly doubt that affected it but I am wondering. The first water pump that did this had roughly 3000 miles on it and this one which I put on after the first one screwed up, this one only lasted maybe 100 miles and they were both brand new Cardone water pumps. When I got them.