OK, I went to visit Demacoz and had a look at how he has connected his up (thanks David).

He has replaced the hard pipe that runs under the intake manifold with rubber hose and in the process deleted some of the unnecessary cooling paths to the rear of the intake plenum.

As Demacoz is not running a turbo he hasn't had to plumb in the water line to the turbo.

Now whilst I am getting closer to resolving this issue I still have a few things bothering me:

1) The original Datsun heater hose is 1/2 and the Ca18 connections are 5/8 yet no one seems to have mentioned a problem mating the two together?

2) Can anybody categorically confirm which is the preferred connection point from the CA18 to the Datsun heater core for the water to go IN. From what I can find online and using my own questionable logic it seems that the water flow is heading down the hard tube under the intake manifold towards the firewall and this should be the one that feeds water IN to the drivers side of the heater core. This is the side of the heater core that has the tap on it to, so when heater is off you are stopping it before it gets into the core....however a few people I have spoken to have the hard tube connected to the passenger side of the heater core.

3) I have discovered i do not have the factory water line that feeds water into the turbo ( if anybody has one spare let me know) and have been unable to find any diagrams that show this piece. Can someone tell me where this line normally connects into the cooling system and roughly what size the pipe connection is (e.g. 5/8 16mm).

Thanks in anticipation......and Happy New Year to all.