I agree with (the other) Ron on this. Some TCs (like the Navion) provide for multiple engines being eligible on different serial numbers. Those you can change with a logbook entry.
In this case, it's a major alteration, and in the past you could have gotten it approved with a one off STC if you could find someone else's paperwork on it. That's rather hard to do in today's regulatory ass covering.
However, all is not lost. There are STCs (Penn Yan's DeltaHawk conversion for example) that allow that modification.