ok i had stock rockers with my new motor and one rocker decided to let go so i decided to put on some comp 1.75 rockers with no shims. so no less than a few weeks later
my #1 cylinder exhust spring broke and i replaced it. Now today after only a few hundered miles the #7 cylinder broke both intake and exhust springs ? Now the only thing i can think is that the spring diameter is too small . the dia is 1.26 and im thinking i should have a 1.44 dia. A friend told me that ls1 valve trains are not very balenced but i know there is something seroiusly wrong . the is with a t-rex cam and here are the specs of the spring ferrea s10075

OD .876 / 1.260
ID .635 / .876
seat press. 175 lbs@1.750
open press 470lbs @ 1.200
rate inch 536 lbs
coil bind 1.030
max net lift .670

installed hight is 1.8

 

Go back to stockers or 1.70 ratio.

Is your preload properly adjusted?

 

I had the same problem. Before CompCams came out with the 918's, they were recommending 3914's. They have since stopped using the 3914's on the LS1's because they found that the harmonics produced by the LS1 were causing spring failure. This may not be your problem but it is food for thought.

 

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What would you like to hear?
You allready have a cam with.600 lifts and you are putting 1.75's on top of that.

Go back to stokers, or stocker ratio
and change your springs to PP golds or similar.

And tell your friend to ... you know... do something.
LS1's are internally balanced and particular to blueprinting.