i curious as to why ccstinger's set up is iffy, that truck should be more than enough to pull your 260 without problems. like i said in the earlier post if you have the 5.0 or just about any small block pulling power is lacking but should be sufficient, you just go up hills a little slower. i also have a 2008 lincoln navigator and that is basically the same as your expedition and i have pulled the 314 with it with no problems at all. im wondering about your setup, tongue weight is a big part of it, as in where the ball is located, gotta find the the sweet spot, i usually find the lower the better, if you dont have enough weight on the tongue it can get washy feeling in the rear end, but too much can have a similar effect. also if the boat is not distributed right on the trailer that can be an issue. but you really shouldnt have any problems with your expedition pulling that boat at all.