I recently purchased a mac x o/r x pipe and it was welded on originaly. the ball in socket style flanges fave remains of the welds still on them. I have tryed to grind them smooth with a cutting wheel but cant get it very smooth. They are only messed up at the rear where they bolt to the catback. Will this cause a leak or will tightening them down good eliminate a leak?

 

Clean it up the best you can. There's nothing worse than thinking it'll be good, putting it on, and having to take it off again to fix it.....

 

I would throw it on and then take it to a muffler shop and have them weld it in. THey would probably only charge about 20 bucks if its already bolted up. My experience is that if the flanges aren't perfect, they will leak.