340. I wouldn't even have 400's in my mind with the allegiance.

Those spine selection charts are just a guideline and haven't changed much since they started making the ICS arrows. Remember that just 10 years ago bows did not have the performance that todays bows have. Just ten years ago a 300-305 fps bow was considered very fast, today that is on the slow slide.

You will need a bit stiffer shaftwith that Ally than you would have needed on a something like an outback at the same specs.

If you don't have OT2 or one of the other programsuse Carbon Expresses adjsutedbow weight chart. It figures that you should be choosing an arrow for an adjusted draw weight of 78 pounds.