So ive decided to install a flowmaster 40 series muffler and a tip onto my 2000 4dr 4x4 blazer. Just curious if anyone knows if you need complete new piping from the muffler back, or if you can use the existing pipe. and if you need new piping, what is a good diameter to use?

 

i dont believe you need new piping.....but i did get the entire thing done.... i went with 2 1/2 piping catback no tip...sounds great

 

You can use the existing pipe. Thats what I have got on right now. Cut the pipe as close as possible to the muffler though. And I mean right at the muffler otherwise you will end up with od sized tube to work with or a tube with a bend in it.