I have an 89 Chevy subdivision myself with over 300,000 miles on it. I bought it used with 148,000 miles on it over ten years ago and it is still running strong.
Back while I was still working, I had the rear springs rearched and an overload spring added. That came in handy a few years ago when I had it heavily loaded moving a complete bedroom set and some other things from Akron ohio down to Florida.
The only problem I really have with it is the poor quality sheet metal which is getting a bit rusty. The rust is what will eventually end the trucks useful life. The bolt-on parts can easily be replaced, but the sheet metal is harder to fix and after awhile becomes too expensive to bother with.
I might wind up buying another used Suburban with a good body and transplanting the good running gear from my current truck to that one just to get around the rust problem.
The Suburbans are just too good to get rid of because they really fill a niche for me in that they can carry both cargo and people in a way that no car can match.
I had a brand new Chevy one ton K30 Crew Cab pickup back when I lived in near Chicago and it started rusting out after it’s second year. That particular engine, a small block 350, was also known for bad tempering (hardening) on it’s cam shafts and was the object of a ‘consent decree’ as a resulf of a federal lawsuit. My cam shaft had to be replaced after only a few years also.
I only got about 69,000 miles on that truck before I got rid of it. On a trip to Arizona and back, it only averaged 6.8 miles per gallon while carrying a slide in camper.
Wonder if this bumper sticker would be understood:
“If you bought a GM car, you owe me money.”