Thanks, Collosus, but boat and dealer are far apart, and I'm not sure I could tell in a short test whether the 4.6 was overloaded or not.

Ford help line still unhelpful; anyone with expertise would be appreciated. Ford said they needed a VIN; otherwise, policy prevented them from disclosing towing capacity. Called back later with VIN, then they said "Research" could help only if I was the owner. Told them I was trying to make a buying decision based on towing capacity. Then they said Research would call me within 10 business days but no promises ... Tough way to sell cars. All I want to know is the towing capacity, with and without weight distributing hitch, for 4.6 and 5.4 models, and why there's a difference. Would also be nice but not critical to know what the cryptic "properly equipped" wording means.

Still hoping...