I just had to replace the cat on my 1990 E350-RV with 460 engine. I had an overheat last year and I believe this cooked the PIP, Engine temp sensor, and the cat.
You might find an old-school shop that will straight-pipe your cat (cat delete), or you can do it yourself. With that old an RV as was pointed out you won't have an O2 sensor downstream of the CAT so no check engine lights to worry about. If you live in a state that doesn't do emissions you can get away with it.
I could not get my cat off by myself so had to have a shop to it, so I had to have a cat put in.
