The back water passages where never used.
Water is pumped down the sides of the engine, then it goes up into the heads and returns to the radiator through the front two passages passing through the thermostat. Do not worry about the pack passages.
One very important item to watch out for is that you put the correct length bolts into the heads. Some of the bolts line-up with some of the push rods. If you put a long bolt in there it will bend the push rod and the engine will NOT run smoothly. Just something to watch for.
Also if you are keeping the EGR valve then do not plug the cross-over passage.
Last edited by scholman; 01-17-2013 at 08:42 PM.
Reason: forgot something