Dog is correct. Yes, you will need something for back pressure. I'll tell you, the converter is not only pressed into the pipe, it has a steel pin on each side. It's in there really good. I used a chissel and a couple hours on the first one. On the second- I figured I ruined them already- I stuck a "T" post in the big end and slammed it into the floor. 3rd whack and it all came out- reducer and all.
