Going with 30lbs of boost in a gsr which crank would be best LS or GSR, i know ls gives you more torque but is it just as strong as a gsr crank.

 

Going by your signature at the bottom I think you might need to rethink your build if it takes 30lbs to make 600hp.

Any way either one will work and will hold the power just fine. The LS will give you a longer stroke and it is what most people use in the B motors.