I recall it having a 425 cubic inch engine, and an open differential, that would smoke a tire at will. (evo.co.uk)
It seems to me that Duntov commisioned and built a 402 cubic inch engine with double overhead camshafts. (corvetteblogger.com)
Nonetheless the 122 - cubic - inch engine in stock trim can shoot the Saab to around to 130 mph and the horsepower boost from the red box, although small, gives the car notably improved acceleration. (articles.orlandosentinel.com)