Fuel tank difference?

[friesza]

What is the difference between a 71 and 72 gas tank....I see the listings and 72 up are listed different...I remember something about being offset but not sure...if so would one from a 71 work...I am thinking about dual exhaust and if its offset I was worried about clearance...thanks

 

[slantsixdan]

'71 has four vent ports and an internal subtank. '72 does not. See here. Physically, either will fit identically, but you'll have problems making the tank venting work safely if you install the '71 tank in a '72-up car without also transferring the '71 vapor catch pipe in the trunk.