It has been two years since I bought any, but I did get non-detergent valvolene (or was it castrol?) 30w since the turn of the last century. The guy at the parts store didn't think he could get any either, but two days later I had a case. Used the whole case in the first two
oil fill ups. Motor ran real nice, didn't get screwed up at all. Bearings looked great, cam still had it's lobes, no problems. I removed the motor during the car's paint and cosmetic restoration, took it apart to freshen it up while it was out. Maybe I got lucky, but it's a 60's motor and I followed the 60's recommendations, even filled the lifters with chevy's EOS and poured the rest of the bottle over the valvetrain as per the manual (it is a BB chevy motor).
Lubrecon, you seem knowledgeable about oils, what is it abut the non-detergent
oil that will screw up a motor "big time"