This may be me being small minded, but when I think American car or truck, I think V8, mostly petrol too, so the appeal of an inline 4 diesel Transit engine is low.
I think you would struggle to sell that on to an enthusiast, but to someone who doesn't know or care, probably not. However I don't believe it'll have anything like the value it would have if it was stock or that they are asking for.
The big thing that would put me off is that I don't think any Transit van engine would have the grunt to haul that thing round and make it usable. Those things are huge and heavy and according to the advert its running the entire running gear which just wasn't designed to carry such a big lump around.
Personally, avoid.