My 61 dodge dart is missing and wont keep running ?

I have a 61 Dodge Dart, slant 6, 1 barrel carb. I just changed the plugs wires points cap rotor resistor distributor coil and fuel pump. The car was running perfect. A couple days later while running the car it made a small backfire, blew a hole in the muffler and now its running with what sounds like a miss its running very rough and after a few minutes it dies. Im thinking is it possibe for the new points could instantly go bad? Any help.would be great