I have a 1984 380se with high NOX readings and cannot pass MA emissions. I tried to reduce by replacing EGR filter AND adding Techron. No go. I also added DryGas before the inspection...readings were higher than first test!

My mechanic said that the only sure cure is a new cat...OEM is $500...Arvin is $70. Is Arvin any good for a few years?

Thanks for input