im new to jets. i picked up a 76 sanger with a 454 in it. i took it out to the lake the first time drove it for about 20 min checked the oil and there was oil in it. so i changed the head and intake gaskets. ran it on the water hose and ran good. took it to the lake and ran it for a while and damn water in the oil again. so i shaved the heads and ahd them checked for cracks all good. now this guy is telling me that i may have too much water pressure going into the water jackets from the jet pump. i noticed a water valve coming from the pump. how do i know if there is too much presure. this is hell because i have to change out 18 quarts of oil every time i do this. and it is hell trying to get it all out. the boat runs bad ass but im just need to get this water problem fixed. any help will be great.