On my 72' for the last few years I have been running a non-EEC tank from a 70'.  I recently swapped to the 72' tank with EEC.

As I understand it, the three lines from the gas tank (sides and middle) run into a metal thing for a lack of a better term (canister?) behind the rear seat.  From there I understand one line runs from the canister deal up to the engine.

If you look at this post you can see the three lines:

http://northstarchevelles.activeboard.com/t48321790/1972-chevelle-fuel-tank-straps-sending-unit-and-cap-75/

I don't want to run a line up to the front (sorry emissions fanatics). 

Can I simply block 2/3 lines from the tank and vent a third?

Do I even have to vent one of the lines?

Or do I have to go to that canister deal behind the rear seat and vent from there (out the 4th port that would normally go to the engine)?

Thanks

yeah thats right you can plug the one to the front of the car and use 2 of the 3. ive had mine that way for 2 years and no troubles there i go not reading the whole post im not sure about the can behind the seat mine is still in service