I just bought the "Hot Rod" Engines magazine (winter issue). There is an article in there on doing minor mods to a crate GMPP 383HT motor to get 500 lbs/ft tork and around 460 HP out of the motor. I was very intrigued by the article and it is a good source of info for anyone building a 383. The numbers they post are listed as true dyno numbers after each mod to the engine.