Just for kicks, I did a search for a late-model Powerstroke engine from a web-based salvage yard network. The lowest I found was $4500, and the highest was $7500.
Don't know what you could get for $1000, but I would think it would be worn out. Even a core engine would bring a grand, I would think.
On a positive note, there seems to be plenty of them out there. I found two or three within a reasonably short distance of my home.
I didn't run any searches for Dodge/Cummins diesels but I suspect they are comparable to the Powerstroke.
I doubt if that included the computer(s?) and all of the wiring harness and other gizmos needed to make the diesel operate.
Plus you will need a transmission, so there is another potential big-ticket item.
You might be able to buy a wrecked truck "on the hoof", so to speak, and strip what you need and part out the rest, possibly saving some money.
Contrast that with a new big-block Chevy 502 "high torque" towing crate (gasoline) motor for about the same money as the low end salvage yard price ($4500).
You pays yer money and takes yer choice. Fun to think about, though! Good luck if you decide to tackle it.
---> Bill