I'm sorry, but I don't think that this is quite correct (may be how it was worded). The tank and vent system that is used in 1971 on (I believe) all Darts is the same as the 1970 California emissions tank and has the weird internal tank. All non- California emissions tanks in 1970 just had one vent that runs from the filler tube near the quarter panel through the trunk floor gasket into the frame - not connected to the tank at all.