So it's smog time again this year, and 2 years ago the truck just barely squeaked by. I borrowed my friend's IR thermometer gun to check the catalytic converter.

As I understand it, there's supposed to be a significant difference in temperature between inlet and outlet (which there was). The inlet was running 3-400? and the outlet was running 5-600?. From what I've read, that means the cat is still working fine, but I have to wonder if that's true. It's 23 years old and has been through some rich/lean conditions with all my tinkering with the carburetor. Is there any chance it's bad but still giving a good temperature increase?

I know it's not going to run quite as cleanly as it's supposed to, given the age, mileage, and the fact that I have one of Ted's heads with a 268 cam, but I'm kind of worried about passing this timeà