My 7.3L PSD does 10K no problem. I've have had Blackstone test it at 5K, they said add 3K more, tested again at 8K, and it was still good to go. This is an engine that uses the oil as hydraulic means to actuate the injectors with up to 3000 PSI oil pressure, so it wears the oil much faster than engines that only use it for lubrication. I'm sure every modern made vehicle can do 10K OCI with modern oils if this dinosaur can.
I had a 3.4L Tacoma before this and ran high quality oil usually Mobil 1 or Amsoil depending on availability, and I got to a point that I was only changing once per year because the oil was still amber coloured, but at the time I heard that oil should be changed yearly at the max because the oil will become acidic. It was usually 14-18K miles at a year, and while I never did an OA on it it's still in the family with nearly 220K miles and it's been with us since 40K, and still running strong/clean. If that truck was 4x4 and could tow more than 5K it'd still be mine.
