Ratwagon1600,
Thanks so much for responding. After putting the motor back in when the headgasket was replaced, I bought new NGK plugs and NGK wiresets as well to use. The only leak that we have noticed so far is a small one near the water pump that might be the cause of the loss of water, but it was just a small amount that was gone when I checked the radiator last night. Gasket wise we only used the headgasket and the rest we went Rebello style by using RTV. My knowledge with Datsun cars is so slim, but I'm am glad to have a friend that knows his way around L series motors. But I will pass your theory behind the problem to him and see what he thinks.
I really appreciate your input Mr. Ratwagon1600
Kind Regards
Peter