If it were me, I'd have a local guy who knows FE engines build the motor. This way you can check daily or more frequently, the progress and what is going on. I strongly recommend not having an engine built by long distance. You never know how it was done and if there's any problem, it's difficult by long distance. When I had mine built, I had problems with low, low
oil pressure. We had to takeit apart and find out the problem, which turned out to be the new
oil pump. If I did this long distance, forget it, it would have never been resolved.
Also, the 427 is the only way to go.
Good Luck.