Are those 3.55's coupled to a 5.4???? If so that damn engine has a real chitty torque curve. It'll pull a stump out the ground, but won't pass a blue hair @ 45 mph while your towing your boat. Been there done that.
I would stay with the gas, it is by far the cheapest cost per operating hour over the diesel. To answer your question, no it wont tow worth a chit...but you will be happier with your checking account in the end.