There's stuck, as in rings rusted to the cylinder walls, and maybe a few pits and rough spots at one place on a few cylinders, and then there's STUCK where the entire engine is a mass of rust.
Jerry
I agree with that,
If an engine is only slightly stuck might as well unstick it and give it a try.
If it's severe it better be a special engine before you spend all the time and money necessary to unstick it and get it running and reliable again.
Here's an example of a throughly stuck engine
http://rides.webshots.com/photo/2932163260080251109xpcYHWBut one that could be made to run again... I decided not on my budget though..
Grigg