23 pounds of boost with a stock bottom end.
There were a few Japanese cars from the Nineties which would end up becoming absolute legends in the world of tuning. The Supra is the best example of this, but even though the Nissan 300ZX usually wasn't at the top of the list, the video shows why it still got some love. The reason why is pretty much the same as all of the other big names in Nineties tuning: the engine could take a tremendous amount of boost with stock internals.
We can only imagine how nervous the owner must have been every time he turned up the boost a bit more, but you can't argue with the results.