I don’t know a ton about foreign motors other than surface level stuff like the 2JZ, Wankel, etc. so please forgive my ignorance outside of US motors.
However, in my eyes, it doesn’t get better than the simplicity and easily available power of the SBC, BBC, and 6BT. What are your all time favorites and why?
The KD and GD series of Diesel Engines from Toyota. While it won’t break land speed records, it will take most pulling, reliability, ease of maintenance. Parts are everywhere. One of the reasons why it’s popular in Southeast Asia.