Abstract: An end cap for an internal combustion engine muffler having a muffler casing defining a muffler chamber. The end cap includes an end wall having an aperture, a mounting structure dimensioned and configured for securing the end wall to an end of the muffler casing, and a tubular member extending from the end wall adjacent to and surrounding the aperture, the tubular member and the aperture defining an inlet/outlet port for the muffler chamber, the tubular member being monolithically formed with the end wall. A method of forming the one-piece end cap for a muffler is also disclosed.