For the life of me where does the brass coolant line go from the tb to where? I know the silver one goes to my idle air control valve. I'm having a dumb moment any help is appreciated. I have a b20b with a gsr head.

 

It goes to the bottom of the water neck on the cylinder head

 

This answer is going to depend on what thermostat housing and what cylinder head you happen to be using with your particular Frankenstein build. If there is not an open 5/16" coolant nipple on the thermostat housing, look to the upper radiator hose neck on the passenger side of the cylinder head. IF there is not a 5/16" coolant nipple/barb there, there WILL be a boss where you can drill a hole (1/8" NPT thread) and install a 5/16" hose barb in the hole... connect a hose between the T/B fitting and the upper radiator fitting.