Many many years ago I had a Plymouth Turismo with a 2.2 engine. I pulled the head to do some porting and put a Mopar Performance cam in it. The dog-gone exhaust tube going to the converter broke off and a new converter was 300 plus dollars. I filler the hole in the converter with JB Weld and man did it get rock hard. It was still in there five years later when I sold it and you know how hot converters get. I also use it to hold the tubes in heads when I port them.
