I have 290k on my 6.2 Suburban, towed PLENTY, up mountains, overloaded... gets hot, cools down, runs fine
I broke a crank in a 6.2, it was badly abused, bad damper
I plow with an '84 K5 Blazer 6.2, 139k, runs like new, starts without block heater below 0f
I have a '95 6.5 Suburban w 309, runs...