I have no personal experience with the model in question, that being said... a quick search on the Grady White website shows that a 257 Fisherman with twin Yamaha F200's on it had a test weight of 6,646 lbs. That figure includes "persons, fuel, water, gear, engines & accessories." What it doesn't include would be the weight of the trailer, which my aluminum I-beam trailer for my 228 Seafarer is I believe 925 lbs? So I imagine yours will likely be at least that, if not considerably more, maybe 1,100-1,200 lbs? On top of that, I imagine that's probably with as little fuel on board as possible, of which the 257 Fisherman has a 135 gallon fuel capacity, and the test boat I'm guessing likely ran at 25 gallons or less to get the best fuel economy numbers possible. So... long story short, if you have a pretty heavily loaded down boat with full fuel, lots of fishing gear, coolers/ice, food, water and so forth... I imagine your towing weight could be upwards of 8,000-8,500+ lbs. Of which I imagine you would want something with a 10k lb towing capacity for a boat of that weight/size, so you aren't maxed out and aren't towing at or above your maximum tow rating/capacity. Per Google, a brand new Ford F-150 with the 3.5L eco-boost as well as the 5.0 v8 both have a 10k+ lb towing capacity, same with the Chevrolet 1500. Again, this is just per Google. My tow rig is a 2010 Toyota Tundra with the 5.7L v8 that has just under an 11k lb towing capacity and she tows my boat just fine. My boat itself was around 5,500 lbs and the trailer, again I believe is 925 lbs per the registration sheet... so around 6,500-7,000 lbs total, and that's with just a half tank of fuel, two downriggers, four rods and a few other small items... nothing crazy in size or weight. Not entirely an apples to apples comparison, but should get you in the ballpark, and as stated above... per Google it appears several of the newer 150/1500 trucks should have more than enough towing capacity to do what you need. Good luck!