i am curious as to what emissions equipment i need to have hooked up or not to pass here in oregon besides the cat obviosly i actually had to disconnect some things on my 1975 mercury to pass the tailpipe test please send thoughts

About 8 years ago, I actually passed Oregon emissions with only a PCV and the OEM crankcase breather. I had an 82 GMC with headers, dual exhaust without catalytic converters, mild RV cam. The engine had 75,000 or so miles on it. I think as long as the engine is in very good mechanical condition (good rings and good valves), the engine should pass.

I don't remember what the Oregon limits were for sure, but I think 8 years ago the 82 GMC HC limit was 220 PPM and the CO limit was less than 2%? I think in recent years the Oregon test procedure has changed, ... I don't live in Oregon now. I think now the Oregon test uses a chassis dyno?

dave w