thanks to everyone for all the help. I called trick flow today and talked to tech svc. They said not to use 1.7's that I need to use the 1.6's and that even though my gt40's have double springs (they are off a marine moter ) that i still need to use their spring kit? I thought they were good for about 550 lift, and the double springs were strong enough to handle a stage1... guess not?