1980 or 08
Your turbo monte is either an 1980 or 1981 carburated 3.8 turbo. You have a rochester 4 bbl carb that sits ontop of a plenum that the turbo plugs into. A very close friend of mine, not knowing anything about the car, took that exact motor out of the car (bad rods) and swapped it for a 454. he scrapped the turbo motor, carb and all that attachments except for the turbo, which still sits in his bedroom on a shelf. Your car was rated at 175 to 180 factory BHP, and about 210ft/lbs of torque. They were a nice motor and a buick product at that. not many exist anymore, and if you have the whole car, keep it in good shape. A turbo monte on ebay with a knocking engine sold for 4500, and it needed a paint job bad. Good luck.