Sounds like the timing is way off, or/and it is running extremly rich. You probably blew the cats if the exhuast got that hot. You need to fix the problem then see if the cats are ok.

How many miles and when was the timing chain last done? If there is no record of that might as well do that while you are fixing it.

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2006 CL500
2009 C300 4matic
1969 280SE
2023 Ram 1500
2007 Tiara 3200