Class C 1994 with e350 chassis exhaust manifold glowing red

Yeah I"ve seen that in my 1989 E350 that also got the tail pipe beet red and blistered the paint on the side of my rv. Problem? The O2 sensors were bad which caused the gas to flow heavily into the catalytic converter and finally caused the internal portions to fall apart and plug up. Result was lack of power and 4mpg.