How far from the spring are those u-bolts? The u-bolts should be right up against the spring, but it almost looks like there's a gap between the bolt and spring. Maybe it's just the camera angle. Also, is there something like a washer under the locating pin that may be hanging it up?
I'd try calling the folks who make the Assassin bars and ask what they recommend for a torque spec and tell them about this. The 60-70 ftlb spec from Calvert will work fine - at least it should.
