broke the cucv work horse

[old Rusty C10]

I thought these trucks were indestructible... I should know better..When Detroit makes these trucks they have crash test dummies, computers etc to test their vehicles but they need the guys that work for me.. If something can be busted they will find a way to do it... lol the motor started making a knock and violent shake after doing about four trips like this but while the truck was empty heading to pick up more dirt... got real lucky apparently it was am exhaust valve spring that let go so luckily its not a major job to replace it. Im replacing it with one through NAPA but im wondering all you diesel guys should I be replacing all the springs in the valvetrain and if so is there a heavy duty aftermarket brand that would take more abuse.. this truck does all the grunt work and I was told that these motors as stock have weak valve springs and don't take well to high revving.. when you need to move loads like this distances you wind up revving it high