fuel tank differences

[chargd72]

Autozone has two different tanks listed for '72 Chargers.  One that says "built before 5/72" and the other says "built after 5/72".  Notice how one is a vented tank and the other is not.  My '72 came with a vented tank.  Did earlier models come from the factory with a non-vented tank?

[chargd72]

But now that I think of it, my car was actually built in '71...   Just wondering why the diffent types 

[Paul G]

Emissions. The later cars, like mine, have the fuel tank venting.

[NHCharger]

My 71 has a fuel evaporation canister mounted behind a removal panel in the left rear wheel well. The gas tank has four lines that run out the driver side to the canister.
My 72 is a late build 6/8/72 and has the four lines that run out the front to a small canister mounted on the cross member.  
Pic of the canister on my 72

[chargd72]

My 71 has a fuel evaporation canister mounted behind a removal panel in the left rear wheel well. The gas tank has four lines that run out the driver side to the canister.
My 72 is a late build 6/8/72 and has the four lines that run out the front to a small canister mounted on the cross member.  
Pic of the canister on my 72

Wow, good to know.  My '72 has the same setup as your '71.  I'm glad I know so I can get the correct fuel tank ordered.  MOST sites claim that all 71-74s are exactly the same.

[471_Magnum]

Emissions. The later cars, like mine, have the fuel tank venting.

To clarify, both venting set ups are functionally the same. The ports are just located differently so they do not interchange.