Originally Posted by Dkrowland81

I agree with Duct tape, the total reason that manufacturers put the GVW at what they did is not what the frame would handle, not even what the motor would handle, its all about stopping what you have. I can tell you that I used to pull a 35' fifth wheel with 3 slides, grossed out at 14,000 lbs, with all my gear and water in the fresh water tanks, etc. My truck handled it fine, and stopped it fine, however I was pulling with a 2008 Ford F250 with the 6.4L powerstroke. But my truck was rated for 16,700 lbs pulling from the bed, thats the other thing that everyone hasnt taken into consideration, the 13,000 lbs that your truck is showing to be rated for, thats pulling from the receiver, or bumper depending on your set up, fifth wheel towing will allow you to pull a heavier trailer because your pulling from over the axles and not the rear of the truck, you could possibly safely pull your fifth wheel because it is a fifth wheel and not a travel trailer, the old books that came with trucks just gave a total trailer weight, they didnt differentiate from fifthwheel to bumper pulling, and there is a difference and no one who has ever pulled anything can argue that point.
I will tell you that I agree with everyone on the motor, while the 351 was a good motor and was tried and true, I have a feeling your going to hook onto your trailer for the first time and the first small hill you approach and the accelerator is on the floor and your doing a max speed of 35mph till you top it, you will park it and get something with some bigger *****. I love diesels, if your going to pull somethihg that heavy you should really think about getting one, you can pick up a late 90's with a 7.3 for decent money. What your going to gain is more efficient towing, better fuel mileage and longevity from the engine. I have pulled with big block gassers and diesels and from experience I can tell you the difference is night and day between the two.
Now, if your just going to the lake 20-30 miles from your house on the weekends and staying in your trailer and pulling it home on Sunday, you can put up with how it tows for that kind of usage, but if your considering hitting the open road and seeing the country, take my advice, trade up, even if the payments are a little higher I assure you you will make up the difference in mileage. Grant you, my 6.4L never got any better than 7.5 mpg pulling my trailer, it was still better than the 5 I would have gotten from the V10 or 460. I have never owned a 7.3 but people I knew that had them said they would get 9-10mpg pulling a similar set up as mine. Food for thought, definately something to think about. There is nothing more discouraging than having that much weight and barely topping hills, you can almost hear the time ticking off of a gas motor with that much weight.
I would atleast consider it, but try your 351 and see how it does, you'll never know till you try.