Ive been making these heads out of old stock heads. They are pressure tested and tapped for a 1/2 npt fitting. I have been running one for about 6 months now and it works great! An aftermarket banshee radiator works perfect with this and I have it set up to thermosiphon. 250 shipped. I have one ready to go but will make more.

looks very good, I know some people use an electric water pump for the setup, I think it is from subaru if not mistaken.

Thanks. Yea a mercedes pump is a popular one too.