This fitting bolts in place where your factory EVAP line returned to the intake.

 After building countless turbo Silverado and Sierra trucks, we wanted to figure out a cleaner way to get vacuum / boost reference to the needed accessories. Whether that be a vac/boost gauge, wastegate, blow off valve, etc, this fitting will allow you to easily route a line neatly to a vacuum block. Its machined with a 8an male outlet so you are able to run either a 8an line or adapt it to a 8an push lock and route it out as needed. This is the exact same fitting we use on our shop turbo trucks. This makes the plumbing so much cleaner and easier to install. 

See picture showing fitting on top of the intake manifold, directly behind the throttle body.