I still have the 78 half ton k10 my dad bought when I was 6. It needs a complete body job and almost everything inside but it still runs and drives and it's 45 years old. If it wasn't for rust and rodents it would still be a solid truck.My best gm was a 78 1 ton crew cab. 454/th400/4.1 rear gear. 323k it got a new gm ho 454 crate. The old 454 ran better than the new crate so it was sold at 328k. That was a great truck. Got 7-8mpg & didn’t matter if it was pulling a trailer of concrete or dry lol
My 2005 Silverado has 260k miles and 11,500 hours, used a work truck for land surveying. It was my company supplied vehicle (I was promoted when someone quit and I was given the newest a 2013 Silverado so shortly after i switched vehicles with my old supervisor "since I was driving shorter distances and the only car guy so I could deal with breakdowns".) The breakdowns never came and I was offered a job with better pay elsewhere and talked to my boss, next thing I knew I had a small raise and owned a 2005 Silverado which I have since been paid mileage to use.
I've had several 80s GM vehicles and all were good but the Silverado has been even better despite daily use all day long.
I just wish they still made them like this.