This RAD Industries Billet Upper Water Neck is for the 2JZ-GE head and will allow you to adapt to AN fittings on your GE engine.  It has -16 ORB female threads so you can use a union fitting for either -16 or -20 for your upper radiator hose.  The upper water neck uses an o-ring to seal to the head so no gaskets are needed.  It has two ports on the bottom, a 1/8" npt and a 1/4" npt for a sensor or for coolant plumbing options on your build. 

 

When installing this upper water neck you need to remove the small M8 studs from head and install the water neck with the supplied stainless allen hardware.