Seeing as there are so many different engines this question is impossible to answer. If you specified a particular engine you might be given a rough idea. Or find someone who has a copy of the ICME manual, which gives manufacturers recommended repair times. Even then you will probably find that there are no "records" for changing engines.
The VW Beetle club in England used to have an annual competition for this. The fastest time for changing a VW Beetle engine was, I believe 12minutes, about 5 years ago.
I seem to remember a Military Tattoo at Earls Court where 2 teams tried to change the engine in a Metro as quickly as possible. The winning team managed it in about 40 seconds I think (I could be wrong). They cheated slightly, because they lifted the front of the car off the whole front subframe, and slotted a new one in.