are the bolts on the downpipe flange that meets the cat thread trough the downpipe flange or just the flange on the cat?

Just the flange on the cat. If your car is older spray them up good with wd-40 and let it sit on there for a day if your trying to take them out.

1999 Eclipse GST 4G63

they are studs threaded into the cat. 12mmX1.25 is the pitch. from my experience if yours are heavily rusted get a nut splitter to break the nut. this way you save the stud and the nuts can be purchased at home depot or Ace.

If you have access to oxy/acetalyne then heat them up red hot and they will come off easy.

Terry

i was just going to torch the bastards off then replace with new hardware. Just want to be sure they werent threaded in to the flange except the cat it self.

If you are going to do that and your new cat has threads on it too, get a big drill and ream them out. Then just get new hardware that slips through - much easier to deal with in the future. I did that for inspection purposes ..... I can have my cat back on for inspection in about 15 minutes, including putting the car up.

1999 Eclipse GST 4G63