Nearly killed myself in the Dart today! :(

When I first bought my Valiant, I was driving it home, and stopped to fill up the tank. Gas came to the top of the tank and came through the filler neck grommet and poured all over the ground. Then continue driving, and hear a LOUD bang. My buddy who is driving behind me, calls and says 'your muffler just blew off the car and you're shooting flames out the back!' All I could think about was overflowing gas tank, combined with flames.