Rancher, I have had 2 catalytic converters ,on 2 Ford trucks, plug up and get RED hot.  One was on a little '86 Ranger(V6) that I had many years ago, and the other, just this spring, on an '86 F150 that we use around here.

   Both times the pickups started to run rough,lack power and backfire,etc.

I was lucky enough to catch it before they started any fires.

   This is probably illegal, but I just took the converters off, took all the guts out of them(smash it out with a bar) and put them back on the pickup. End of problem!! Made them sound cool, too!!