What are normal temps out there. I recently went back to a single exuast with a cat for smog reasons. I just shot the temp with a inferred and it was ofer 600 degrees. I actually melted a tub uf baby wipes on the floor.
I am thinking too much carb. It is on a AMC 360 with a Holley 750.
I was planning to go to a smaller carb or F.I.
I also am going to go put a dummy spool in place of the cat and throw the cat on every 2 years.

Yeah, 600 is way to hot, It should be 300 or so in front and approx 100 deg. hotter in back. If it is that hot, it is probably turning purple and melting the substrate inside. Usually, that kind of heat is caused by being to lean.