I have a 460 in my Eliminator jet boat. 85motor hours ago i had my Cobra jet heads rebuilt. They had to be pinned. Just found water in oil. Pulled heads and they are leaking past the pins. Had my local machine shop set up a set of E3V A2A heads with stud mounts for roller rocker arms. Boat runs great but still getting water in oil. Any ideas. I doubt the block is cracked. it has never gotten hot. Can water enter through the front somewhere ie timing chain cover. Also, when I put the head gaskets on the left side gasket was stamped front facing up. The right side had to be put on with the front stamp facing down. i was told this is correct from the machine shop. is this correct. Help