Hey guy's I have a 1979 Sanger SuperJet with a blown 461 BBC Pushing around 900hp. I have alot of cavitation out of the hole. I have heard about a pre-impeller but don't know much about them??? I Pump is a Berkeley jg with a bronse A impeller. The Jet takes about 15-20 seconds to "prime" is the best word I can use to discribe it before the boat will start moving when I first set it in the water. After the inital "prime" it move right away after it been sitting (in the water). Anyone know what the deal is???? It did not do this prior to the "rebuid". The pump was rebuilt about two years ago by J and A marine in Sac. I really love this boat and have lots of time and of course $$$$$$...... money in it it run ninty three on GPS BUT..... I want to go faster da....... So what can I do????