Can I put a 2000 Ford Explorer motor into a 2001 model?

Can I put a 2000 Ford Explorer motor into a 2001 model?

You have not indicated which motor you have with your question.
Most explorers have a few V8s if I'm correct.
If it has only a V6 then that's all you can put into it, and the laws are just so with this type of question you have here.
Any computer won't, allow for changing a V6 to a V8 because it won't be legal to do it and it will never work, and many mechanics will back me up on this fact.

If you replace a V-6 with a V-6 OR a V-8 with a V-8, yes. If you want to go from a V-6 to a V-8, it will take more work.