Like a Rock (Let's document it)

[Alex V.]

*Bob Seger song plays as Sam Elliot drawls, "Chevy trucks - the longest lasting, most dependable trucks on the road."*

I'm only 24, but I grew up around 60's, 70's, and 80's Chevys in stock form, doing legitimate work, proving that slogan true time and time again long after they were new. It seems that image is fading - maybe it's due to the age of these trucks, owners who couldn't keep a deuce-and-a-half in one piece for very long, let alone a consumer product, or whatever - but I believe the only line of comparable vehicles that were generally more reliable and usable were the GMT400-platform trucks, and then only so far.

So, limiting it to basically stock (at least 90% stock drivetrain) trucks from '67 to '87, what's the most miles we've seen accumulated without undue heavy repair (which includes whole engine rebuilds) to drivetrain or chassis? Also, what fuel economy have you scientifically documented on afore-mentioned machines that you felt was particularly good given the drivetrain configuration?

I site my dad's '86 K20 and my '85 C3500. The K20 was bought new by him, over 361,000 miles to-date it required two valve jobs, one transmission rebuild, and currently needs ball joints.

I got my C3500 in '07 showing 77,000 miles. Given the overall very good condition of the truck in '07 it likely hadn't had an engine or trans. rebuild, though now with 120,000 it needs valve seals and a trans. rebuild. Burns/leaks a quart of oil every 1,000-1,500 miles but the only thing that indicates it needs internal attention is the rockers singing their little clicking song at warm idle saying the valves need adjusted. I've had to replace the upper A-frame bushings, pinion seal, and rear springs, but nothing else I'd consider outside the realm of long-term maintenance parts (brake calipers, shocks, etc.) I've documented 12.5 MPG on many long, empty trips, which I don't think is bad for a 5,300 lb. truck with 4.10 gears.

Who else can chime in?