Ok here in my opinion is what you are gonna want to do. Pull loose the drivers engine mount and trans mount and rock the engine to one side.Pull the oil pan.Then pull a couple of rod and main caps and see how far the bearings are gone.If brass is showing and since the engine has high miles then get ready to pull it and rebuild it.
If not reassemble torque correctly and go pull the head and replace the gaskets and do what I said above about the oil.And you should be good to go except for the wastgate and scan tool.
To adjust the wastegate I would back out the threads until it is just barely holding the flapper closed.Then hook up a boost gauge along with a good scan tool like scanmaster or direct scan.
Also a good adjustable fuel pressure regulator and fuel pressure gauge would be helpfull for tuning.
93 to 94 octane gas or higher is almost a must in these cars.
Then run it while recording data and slowly adjust the boost until you get knock retard . Then back it down a turn.1 turn equals 1 pound of boost generally.
You also want to keep track of o2's at wot and make sure they stay in the .740 to .820.The higher the number the richer to mix.
While you are at it check to see what kind of chip you have in it to make sure it is best for what you have.
As far as rebuilding and moderate performance.Go to
http://www.gnttype.org/ and search for rebuilds or performance recieps
Be carfull what machinest you use or if you pay someone for a rebuild these engines are different and you really need to deal with someone who knows turbo buicks not just a good rebuilder.They are totally different animals and you will regret it later if you don't.
Hope this helps I know it is alot of info.If you have any questions feel free to ask or post on this board and we will help as much as we can. Kevin
