Hi
I did have some problems with valve rockers breaking up during cruise, which I just newly installed and didn't even drive for 500 Miles.
2 intake valve and 1 exhaust valve rockers , stamped steel, just broke like glass.
The intake ones don't harm the engine as it just doesn't get any gas to burn , but the exhaust rocker made a hell of noise as the burned gas had no way out .
So I reinstalled the old original GM stamped steel rockers and everything works fine, but I decided to do a cylinder compression test to assure nothing else got damaged.
What do you think. Slight difference in the pistons, but all pull well over 11 Bar.
Cyl 6 was the one with the failed exhaust rocker.
I hope the difference comes from the old, still original and never touched L71 heads ?
Gunther

Gunther,
Sorry to hear about your rockers. I had number six exhaust break on me last summer. Scares the hell outta ya. I was just driving around town doing about 35-40 and it just broke...no rhyme or reason. Well, at least neither of us had any permanent damage. BTW, mine are all original GM parts so don't blame it on a replacement part, it just happens.

Hi Glenn
Yes, your right if it happens once evry 100.000 Miles, but I just installed this complete new set this winter and didn't even drive 500 Miles, and not only one, but 3 each rockers broke.
Sorry, I do blame this to bad material.
The answer of the company that sold them to meis :
we bought those rockers from a company, that went bankrupt , as a bunch.
We sold 400 sets so far without complains ?
Funny thing is that they where offered under the companys proper P/N ?
I guess, you can't beat originals !
My rockers all broke at around 4.000 RPM on the highway. Intake failure is no big deal, but the exhaust rocker, man what a noise and blowback into the carb.
Gunther