The vented fuel caps are different than the vented fuel caps. My '69 had a replacement tank but somebody reused the original non-vented fuel cap which fit loosely. My '69 had the external fuel vent tubes also. I bought a vented fuel cap from NPD and it tightens down like it should. Unfortunately, it seems no one reproduces the fuel tanks with the filler neck vent tube. If I had known this I would have saved one from a wreck Firebird.
