New engines for the Ercoupe

Ok gang,

I have a question (or more). I was doing some thinking regarding ercoupe powerplants...

What is the process to change out the old C85s or O200s for something like a Rotax 912? I've been diving through the FAA regs and it seems doable. How do we do it? In my mind there is no reason to not look into engine upgrades for newer, more reliable, fuel injected options.

Thoughts?

Sean