Well I had problems getting my y-pipe to go on, and now it wont come off! It has a ball and socket flange without gaskets and I took all of the bolts out and hammered it and pulled and it will not budge. I used black silicone to try and seal the flanges, so I dont think thats whats holding it together. What can I do, I need to put some sealant on my oil pan. Thanks guys.

 

the heat cycles probably made it contract some so the joints are stuck at the headers. You need a giant prybar or something else to pry it off 1 side at a time.