Fuel tank vent.

I am using a similar filter on a LS1 in my truck. They came in corvettes. It's actually a regulator and filter in one. Whatever the engine won't use or what's over the psi of the regulator it diverts it back to the tank. I wonder if it's a similar deal.
I'm not sure. I've never used one like that. The one Dana67Dart was referring to is a filter, with an extra outlet, if it's what I'm thinking