According to the the Mitchell Emissions Application Guide the 1986 Winnebago equipped with a Chevy or General Motors engine (in any configuration) was not equipped with a catalytic converter. This means that if this RV has not had its emissions systems modified or tampered with in any way and its exhaust emissions fall below CA emission cutscores, it can pass the smog check and allowed California registration. You do not need to add a CAT in order to pass the smog check in Cali. You only need to ensure the emission parts have not be tampered with and everything is as it was when it left the dealership. Obviously it will have smog parts which were replaced over the years, but as long as nothing was removed, added, altered, it can pass the smog check.
