Water tank bracket most likely. It goes under the coolant tank that's on the side of your intake manifold... that's my best guess.
I had the same problem with my T1 top feed fuel rails. It is the water tank bracket and also holds the power steering lines in place. Be mindful of where the power steering lines sit relative to hot exhaust components without that bracket.thanks guys, i couldnt figure out where it went because it wont fit with my new fuel rails.