There's no real reason to think that adding catalytic converters means the power will go away, modern cars have them too. However, even those require some electronics. The old two way converters won't do much for NOx emissions, the modern three way have been in use for nearly forty years now but usually need an O2 sensor to check for richness, and air injectors to add oxygen when needed. Feedback carbs were part of this solution, fuel injection does away with air injection in most cases.
Very true to some extent...
IMO....When in 1975, when the catalytic converter were first introfuced, the origional design was to reduce/eliminate both Hydro Carbon (HC) and Carbon Monoxide (CO) emissions thru thermal oxidation over a platinum coated substrate. Many manufacturers used an engine driven "air pump" to furnish the oxygen needed for the converter to work....at least in theory. I think, in reality, the air furnished by the pump, simply just diluted the HC and CO emissions, allowing the vehicle to achieve emission requirements. The origional GM converters used little pellets in the housing while Ford and Chrysler ised a "honeycomb" or monolithic dedign, superior in all regards, due to the substantially less exhaust back pressure and a better conversion reaction.
When regulations required NOx emissions reductions (thank you California), the 3 way converter was introduced. The converter contained the same platinum catalyst and a palladium catalyst was added. Then the infamous Exhsust Gas Recirculation (EGR) dystem was added for further reduction of NOx. Compression ratios were lowered in an effort to reduce NOx formation by lowering combustion chamber temps and to allow operation on lower octane unleaded pump gas (removal of the tetra ethyl lead fraction which poisions the catalytic converter) rendering it ineffective. Engines were modified to operate on unleaded fuel (hardened exhaust valve seats), open chamber heads to reduce quench areas for HC and CO to "hide.
Can "old cars" pass today's emission requirements? ....not likely....but IF that requirement comes to pass, then it should be limited to the year of the vehicles manufacture. AND to have exemptions for these cars based on, perhaps, annual accrued milage. For example, my RS23V0A******, is in storage for approximately 8 months/yr, emitting ZERO emissions. In my example, the car is driven less than 600 miles per year. With a milage exemption, based on the proportion of total annual emissions, for 1970, would be 4/12 based on months of use OR of total annual milage factor of say, 12, 000/yr would be 600/12,000 x100 for a milage factor. Just my opinion of course.
BOB RENTON