If your going to do anything with the up-pipes just order these and have them on hand before you start. Even with soaking in penetrating oil and a bit of heat from torch still had to cut both passenger side bolts off and one of the drivers side twisted in half while trying to remove it. SAVE THE HEADACHES just cut the old ones and put in new.

These are in the 99-03 section but fit the earlier 7.3's as well. Order these in advance of starting any up-pipe work and save yourself a ton of time and frustration. Removal of exhaust hardware is always tricky. Just cut it all off and replace it.Even if its bolted on and you round the bolt heads,you can grind off the head and get the part off ( y collector). once its on the bench,you can soak it, tack a nut on the bolt,and remove it way easier than under the truck. New hardware goes back on way easier too. These bolts are factory fit so it's a job done right at minimal cost. Buy the bolts FIRST, then start the job!