You probably would be ok, but you are risking a lot. I looked at oversize fees recently and they are $200 per flight on some of the major US carriers. I'd go with a smaller bag.

Remember these are soft sided bags and will bulge somewhat increasing the size a bit. Further unless you are carrying styrofoam you are likely to overpack weight wise with a bag this size. Most carriers limit you to 50 pounds in the states. On a recent trip I just straddled that with a 28" Eagle Creek.