If you do look up the Smog system requirements they weren't enacted until long after the 228-248-270-302's were built. But later in my state we started to have to add and modify a system on our older engines. Why not try a good Parts House and ask them if a kit is available and then ask this question. I had a dual quad Chev 283 and the required Smog add-on really caused me some problems.
Normbc9