just wondering what the stock vale springs in an lm1 350 are good to as far as lift any ideas would help

 

About .500. But they are weak, especially with > 20k/miles on them. They are ok with mild cams, but if you are thinking of installing something more aggressive, install some of the drop in hiperf springs offered by all the cam companies. If not, the valves will float around 4,500 and the engine will fall on it's face.