I am going to replace my catalytic converter but see that the flange mounting bolts are rusted out and seized in place.
What is the best way to handle the job without the use of a cutting torch?

Also, the support attachment for the exhaust pipe (between the manifold and the CAT), normally tied to a bracket (attached to the transmission), is rusted out -gone-. What does this support do? Should I take care of fixing that pipe too?

Thanks

Rich

Yes, you need some kind of grinding or cutting wheel to deal with the flange bolts. And I would fabricate some sort of attachment where the broken one was. I think it stiffens the front part of the exaust so it won't tend to flex & crack at the manifold flange. (But I've seen them missing for years too, so I'm not sure of their importance.)
--
Bruce Young, 940-NA, many 240s (one V8), '73 142, '71 144 (ex circle track car in CT), '67 144 (new), used 122 from '63 to '67

I just grind/cut them off with an angle grinder which takes about two minutes. The hanger points are pretty obvious under there also that usually attach to bands that go around your muffler(s). I'd look the entire system over and fix everything while I was at it. It's a big waste of time and effort to splice in new parts to existing junk.