Got back to my garage after a short drive in my 73 Challenger, once I had opened the garage door and walked back to the car there a fairly large puddle of fuel on the floor leaking onto the diff, quickly looked underneath the car but could not see where it was coming from, so started the car again and looked underneath but no leak, I did notice this pipe(see below pics) just above the diff in front of the tank but could not confirm if this was where the leak was coming from, is it some kind of fuel overflow pipe ?

I did fill the car up yesterday to almost 3/4 of a tank so is it possible the gauge is inaccurate and I have just really overfilled it ?

I haven't owned the car long so i'm not too familiar with the accuracy of the gauge yet

I put the car back in the garage and checked again for any leaks but again there was nothing ?

Thanks for any help