I'm not going to make a science project out of searching for these again...did it before when i was trying to decide for myself if it was a good motor,but here is at least one offhand on the forum....man i could spend hours finding these:
Both of these were my grandpa's vehicles. '97 Z-71 extended cab, Vortec 350. He ran it 330k miles then gave it to my cousin who ran it 20k more and basically gave it away on trade in for a Cobalt she sold a year later. It never burned a drop of oil. The second was his '01-02 1500hd 6.0 4x4. Traded in at 300k miles for a good price (in excellent shape) on his '07 f-250. Didn't burn any oil either. Both engines were not only mega high mileage, but were high-idled for a/c in 100+ degree oil fields every day for hours a day.
(not a 350
My old s10 2.2 5sp had 310k when i traded it, used 5w30 maxlife blend and fram every 3-4k
is a 350: Just posted pics and info on my 89 Caprice hitting 500,000km's (310k miles) on the original engine still running good, with dino 5w30 oil changes ever 3-5k miles.
We run a fleet of Savana 3500's in some of the toughest duty imaginable.
One of our vans has 335,000 miles on it, driven daily at 9000 pounds. 2004 6.0 Gas V8 with oil changed by OLM with Amsoil SSO and Ea filters exclusively.
Our best van ever was wrecked at 400K miles, 2000 5.7 gas V8, and the engine and trans are in my sons friends car now for a year! Still runs perfect and no knocking or oil consumption.
Stepfather has a chevy work box truck with a 350 in it that now has 320k miles on it in PA. No internal engine work and gets changed with dino between 3 and 5 k miles. Still in use
A friend has a 99 Silverado Classic 5.7L with 260,000 miles on M1 10-30 with 15-20,000 mile OCIs.
Also, we've got a '94 Suburban with the 350 TBI that has 260,000 miles. It has been fed a combination of Valvoline dino 10w-30 and HDEO 15w-40 with a current fill of Maxlife 10w-40. Still runs like a top.
And these are just responses to a post i made on the oil forum, for high mileage stories on dino and synthetic, of any car...overwhelmingly many of them were Chevy and many were v8s and 350s in particular.
gotta go more later...
Have seen much higher mileage than these more often than not as well.
Note...additionally, many if not most of the engines I quote with high mileage are in trucks, and consider a few things about that...
trucks are not typically "garage queens"....they are pushed hard, put under load, and used to haul, work, tow, in whatever conditions are present at the time. they are also prone, in many cases, to not being "babied" as far as maintenance either, for a variety of reasons - knucklehead owners, lack of time, etc...
another fact: Chevrolet makes the "longest lasting trucks on the road"... and guess what engine is in most of those trucks, probably 75 percent or more would be accurate: yep, you guessed it, the 350. that being the case, refer to the above operating conditions and maintenance that trucks are typically subjected to, and the former being almost if not totally exclusive to trucks in particular, and you got yourself a winner.
350...for the win!!