i got 130,000. a guy i work with has got over 200,000 with the stock tranny. they are a good "stock" motor. you start doing serious modifications. supercharger, radical cam. etc. they don't last long. they were based of the 350s and the 350s were a dam good motor.

 

I changed the tie rods, ball joints to make a good Chevy again, and was discouraged by a starting problem
on warm days. After changing the starter and ignition coil, I discovered it was the distributor rotor loosing sparks and
a new distributor assembly was only $45.00. The whole distributor changed made a new Chevy again. The engine
does not use any oil at high miles. I change it at 5000 miles, and have a new Chevy again after the mystery of
hard starting during warm days was solved with the whole distributor changed out. Put the old one in TDC at the mark and then put the new one in as a easy swap out with only one bolt holding it in. Turn the engine with the generator
hex bolt to TDC, marked by the old distributor or number one cylinder, (first one to the right from the front) to TDC
by having the pressure exhausted and then the suction starts.

 

Mine is at 135k miles. If there is a worry on my part it is that I might have an oil leak from either the front or rear crank seal. Since I got it at about 88k miles I've been religious with oil changes and keeping it from overheating. I recently switched to synthetic oil and will do my first oil change on it at only 2,000 to 3,000 miles as I expect the new oil to absorb lots of old gunk. I'm hoping to get at least another 50k to 70k miles out of it.

BTW, I'm encouraged with number of motors I hear of that have gone well over 200,000 miles. :-)

 

I've a 94 4x4 at some 195k still running strong. Tune up three years ago, some vacuum lines. Oil consumption still normal and still going strong.

Building an engine for it but not that I would need one now. Just for the fun of it.

 

'97 LT Blazer 4x4 here with original engine and trans (afaik) and I'm at 265k miles. I had to replace the lower intake gasket last summer at around the 260k mark, so I'm optimistic she'll make it to 300k for me. ::knock on wood:: The guys at the oil change shop always remark on how clean the fluid is. People can be religious about the type of fluid you use and for how many miles you stretch it...I use Max Life 5/30 Synthetic for High Mileage and change it every 3-4k miles. I change my trans fluid every couple of years. I thought I was doing pretty well 'til I met a home inspector who had 400k on his 1500, so these days I'm not nearly as proud of my greater-than 250k miles as I used to be. lol

 

I met a guy with an s10 who had 927xxx on all original. And I just sold a zr2 s10 about a year ago with 854xxx all original. Really I guess it's just based on maintenance and luck of the production line...

1st edit: Forgot to mention that's in KM

2nd edit: 875xxx not 854xxx

 

I've got 332K miles on mine. Other than the usual problems, mainly fuel system, it's been good to me. Never been in it past the manifold. Original transmission. Was leaking some oil, but it was the oil cooler lines. Fixed those (for the second time) now it's all tight again.

Did a compression test on it about two years ago, can't remember the exact numbers, but they were all damn near the same, and fairly high, considering the age.

They're good engines. Like everyone's said, it's a 350 small block, minus a cylinder on each side. Maybe not the most efficient, or powerful, but it'll run forever, as long as you do your part.

 

I had a 1993 GMC Sonoma w/ a TBI 4.3. It had 240,000 miles on it when I sold it. The only problem I ever had out of it was that the freeze plugs started to leak antifreeze. The first time I had them replaced, they didn't leak for about one year. After the second time I had them replaced they only lasted a few months before leaking again. I sold the truck to a guy looking for the square body to make a V8 street rod.

The 4.3, in my opinion, is bulletproof when properly maintained.

_____________________________
1999 Blazer LT 4dr, Auto-4WD, AT
Bilstein 4600 Series Shocks
Axle: 3.42:1 w/ Eaton Detroit Truetrac Locker
Tires: 235/75-15 Michelin LTX A/T2
Gibson cat-back exhaust
K&N CAI
Hypertech Power Programmer Tune