I had my catalytic converter go bad on my '91 Ford 460. I was 200 miles from home (S. Cal) or trusted mechanic. My mechanic told me it would be a good idea to find out why the cat converter went bad before I installed one on the road. Didn't want to burn up another converter. I had a muffler shop knock out all of the guts of the cat converter with a long steel rod and re-install it. Drove it home and had everything checked out, just a bad converter. The motorhome ran so much better I ran it with the cleared out converter for over a year. That is until I needed my next CA smog cert!