This car is actually a pal of mines (20k miles) and he has not pulled the motor yet. But here is what happened, He had a Vortec supercharger installed by the dyno shop here in town they tuned it did all the appropriate changes and when he picked the car up they told him his boost was running right at 12 PSI and to run no less than 92 octane. One week later the car makes a loud knock and when he went to restart the car it turned over like it was way advanced time then started and knocked very rapidly. I am guessing a spun bearing. Whats your guess here of the procuring problem?