[78w72]

My 72 had that EEC emission thing, I removed it and used a new non vented tank since I didnt want to run the lines and keep that, my other cars with the charcoal canister set up I eliminated too. Never had issues with vac/psi in the tank or smells when parked in the garage.

On the 72, i use a early style vented cap along with the Tanks Inc vent that has a rollover protection feature, installed as high up as possible mounted to a bracket on the frame or trunk floor near pass side. Some on here dont like the vents but others use them and they work great... i have zero fuel slosh or seepage with hard driving on the street or low 11s at the dragstrip and it did fix a slight vac issue i had at first since the cap only vents out, also no slosh or seepage using the aftermarket but OEM style cap.