How long will it run?

[Tazman]

I have given a lot of thought lately of replacing my 350 in my 87.It has 214k on it plus now I am driving about 70 miles per day to what I consider is my last workplace. It runs just fine but works a little harder when the air is on. I am wondering if I could get 300 k on it before it gives up. Any body out there having that kind of luck?

[LTZ C20]

As long as you have good maintenance habits, change your oil regularly, and your air and fuel filter as needed and fix any issues as they arise. There's no reason to fix what ain't broke, run it till it gives up, then replace it. Worrying will only make you feel bad and give you nightmares.

[Peter S]

My 79 K10 went over 300K miles. It ran good but the original clutch would slip without too much effort. In the end the body just about rusted off of the chassis.

[Stewart G Griffin]

Do you have AAA?

i would just go until it doesn't run anymore or is giving problems-----which in my case the time has come 

[LTZ C20]

The 350 that was in my truck was not the original. I new nothing about that engine other than it was a 4 bolt 350. In its 3 year life span with me, I never once changed the oil, it leaked just enough that when it started to tap a little I added 1-2 quarts of cheap regular O'Reilly brand oil. Was good for another 2-3 months. Never once changed the filter. When I finally replaced it, it was because it was chewing thru oil like crazy, valve seals and piston rings. The rotating assembly and cam were good tho. I was NOT nice or gentle with that engine.

[XrayTedd]

I have a buddy with a family owned 88 k5 that's sitting on about 400k on the original motor.   The truck overall has been kept real clean and well maintained. Although even with proper maintenance motors will start to tear themselves down. Ultimately the life span of these motors come down to how well the rotating assembly was balanced from the factory. The factory had a wider range of "acceptable allowance" than what is typically used by the individual engine builder. 
In short..... it's a crap shoot. Lol

Sent from my SAMSUNG-SM-G900A using Tapatalk

[fitz]

  I few years ago a friend of mine gave me his 87 V10 (still a k10 in my mind). He was the original owner and put over 250k on it.
  It was a nice truck that he ordered new, it was a short bed Silverado with a 350 TBI/700R4-208/3.42 gears. Unfortunately the New England winters had taken a toll on the body.  The drive train was still going strong with 250k + on it.
  He gave me the truck so I could part it out. The drive train was sold on Craigslist.  I'm guessing that motor is still going strong today in someone else's truck.
  My buddy would still be driving his 1 owner truck had it not rotted out.
  Yours may have more life in it than you think.

[jrbarrie83]

My dad's '80 k10 350 has well over 300k and runs beautifully. Had basic maintenance done, clutch work, carb rebuilt, but the engine itself is all original and still going strong.