Cummins parts and cut off dates

[3406E]

As for old motors like the n14 and so on. When does Cummins decide to stop building rebuild kits for them? You can still get a new rebuild kit for an n14 but Other parts like oil/water pumps, injectors etc you are only able to get Cummins rebuild on those. I see this is the case up from cm570 to cm871. Are cm570s to cm871 slowly approaching dinasour era? I never really checked if you can get brand new bolt on parts for cm2250 and upwards or is it the same case? In my opinion I think the lowest I would run is cm870 or 871 when it comes to parts availability.To add, last year I saw a young guy in Houston around my age running a 400 Cummins in a 359 probably early 80s manufacture said he literally just got it rebuilt pulling a step deck lol. It was pretty cool though. I will add picture if I find it in gallery.