Don't use it for a return or plug it unless you make other arrangements for a vent. That 1/4 line --which went to the canister--IS THE vent
As said above.......you can go to MyMopar and download service manuals. These systems changed over the years.
1....Nothing before 70 had them, and only some 70's, CA state notably
2...I think but not sure that 71/ later all cars had it
3...First few years they used a big long tank up in the trunk, "vapor separator."
4...Later years incorporated this function into the tank itself, so no separator in the trunk
5....Pay extra attention to fuel caps. They changed in the years with these systems. "Somewhere on here" is a thread on the different caps
