LS7 valve springs work in a big block

I looked up installed specs on my heads and valve springs should have installed height of 1.850
I found a complete set of LS7 behive springs and retainers and they say they are longer than all other ls engines. Their installed height is 1.959 but it looks like the reatainers set up farther and on the LS site it says to shim them to 1.850 for high rpm. I am looking for a .520 lift but only 6000 rpm. The regular ls springs are 1.800 but can handle .500+ lift