My K5 Blazer Story.

[Zoomad75]

Since I live in a non-emissions county, no plans on Cats. This system doesn't fire the injectors sequentially, but in a batch fire style similar to the old L98 TPI systems. Based on that, one o2 sensor is enough. The stock style downpipes off the manifolds do have bungs for o2 sensors, but the left side will get a plug.

I wasn't aware ALL LS engines were CARB approved. I know the GM crate Erod engines were, but thought the ruling was the vehicle with the newer swapped in engine had to meet all the requirements of the year of the engine installed. Meaning, cats, evaporative emissions systems and all the other goodies. MEFI for in my form in a 91 probably wouldn't pass CARB's muster. If anybody in CA is looking to do this kind of swap, you need to do the research with CARB to find out what your swap will need to be legal.