The fastest time for disassembling and rebuilding a V8 engine was clocked at barely over 17 minutes during the 2023 PRI Hot Rodders of Tomorrow competition. I was surprised that no power tools were used.
https://www.hemmings.com/stories/2023-pri-show-hot-rodders-of-tomorrow/?
https://www.hemmings.com/stories/2023-pri-show-hot-rodders-of-tomorrow/?