'97? I would reconsider. There are some drawbacks to the ford diesels. Unless they have changed their engines, the diesels run great, reliable for a while, then...you will regret owning one!
The engines have a special computer driven fuel injection system that costs about $1500 PER CYLINDER for parts alone, and that does not include the highly technical labor required to fix it. Once these engines get about 10 years old, the cost of an engine repair makes it not worth owning anymore. The ford diesel WILL NOT OUTLAST a gas engine, not because there is anything mechanically wrong, just that what must wear out is more expensive than a new engine, which is more than the used truck will be worth.
They don't have a conventional fuel injection pump, and No! You can't work on it yourself. At all. Except maybe to change fuel filters. And Yes! The dealer knows these things and will break it off on you when the truck finally needs a repair.
If you plan on buying new, and owning it for only 5 or 6 years and then dumping it on some unsuspecting fool, the diesels are fine. Otherwise, buy the gas, own something you can own for 15 years. Furthermore, as more people get burned by this engine, it will become well known that you should not buy a used Ford Diesel, so I suspect that the resale value will be low.
I know I have no intention of owning another one. Mine is a 1995, and it cost me over 4 grand to get one cylinder fixed last year. The gas engines work just fine for me, and I used to prefer the diesels, back when they had injection pumps on them.