My old 85 Toyota SR5 Pickup had 297K on its original motor, never rebuilt and I never replaced the timing chain. I had to do the tensioner once, but never got around to the chain which was supposed to be replaced every 100k miles. It did go thru its share of alternators and starters, but nothing more than that.
Didn't smoke, passed all smogg tests, but didn't run as fast when it was new, gas milage was decreasing, but it ran like a clock...
I miss it
Ended up selling it cause it didn't have A/C