Low mount water inlet configuration
 

Going to summit today and was going to pick up some of the AN fittings and braodes hose to start mocking up my water lines to the efr.

I ordered the Hawley billet water inlet, I was originally going to have AN fittings welded in place if the stock rear port and a side port added. Now I think I'm going to tap it for npt an fittings instead.

My main concern is if it would be better to tap the rear for -12 and run that straight to the heater core with barb on end to connect directly to stock hose and then tap the side of the Halwey with a -6 npt fitting and run the return from the turbo there.

The other option I considered was to buy a 12an female to 12an male that has 1/8npt on the side if it. So it would be -12 npt on the back of the water inlet, with the -12 pressure adapter installed and then to the heater core. Then a 1/8npt to -6 an for the turbo return. Just not sure if the harsh 90 degree turn on the pressure fitting would impede flow where as directly to the side of the inlet would give a more direct shot into the pump inlet.

I'm starting to think the 1st option is going to be the better option. My biggest concern was jacking up the tap and ruining the inlet. I guess if I did that I could then have a fitting welded instead.

1/8 npt port is too small for the water return. You will need a 1/4 npt or 3/8 to not bottle neck it and restrict flow and prevent thermal siphoning. Also the heater core tubes are a -10an size(5/8)

That was basically my concern, it would be too small. Luckily I am going to run the Kraken ac/pc compatible water inlet he posted on Facebook a few days ago, it has a barb for return from turbo and a barb for the heater core.