FYI: engine swaps are beyond a the limits of a field approval. It changed about 25 years ago.
You also wont be able to navigate the approval process without the assistance of a DAR and DER unless you want to wait 20 years to complete the project. And even though a One-Only STC cant be sold out right you can sell the data package or develop the data package so that it can role into a Standard STC.
Regardless, in my experience, best first step is to sit down with a local DAR, pay his hour rate, and go over your project plan. He or she should be able to give you a close idea of the specific process you need plus an estimated timeframe and cost. Then you can start to make calculated determinations vs guesses. While it may seem a daunting task its doable and engine swaps are still done on a semi-regular basis across the industry. If you got more questions, post them.
