Awesome project! It's hard to believe that such a clean Chevelle can be found in Norway without having to ship one from overseas. You are very lucky. And it's great that you had the opportunity to drive the car for a while before tearing it completely apart.
One suggestion: Look into the trans controller from Powertrain Control Solutions.
http://www.transmissioncontroller.com Their product is very well suited for turbo cars as it allows for dual load sensor inputs--MAP and TPS. You can set it up such that the transmissions shifts a bit more mildly when the controller sees vacuum and then aggressive when the computer sees boost from the MAP sensor. So it will gather load data from both the TPS and the MAP using one as the primary input and the other as secondary input for very accurate and reliable mapping. Not a necessity, but useful. Perhaps Compushift can do this also.