I like Nick's Garage also but I cringed when he wanted 600 hp out of a 440 and he drained oil to achieve it. Bad part he cracked the block from stress at a water jacket that was ultimately fixed.
They did a lot of little things to get that 600hp out of a street engine on pump gas; draining off a little over a quart (out of 8) of oil was but one of those. Welded up the horizontal "seam" crack and put it back in the car and off it went, all with the customers' blessing (if I remember right, it was for his brother, who was in on the decisions made).
Draining oil from the pan is an old racing trick to increase power. By running less oil in the pan it reduces drag on the crank, thereby increasing the ability to increase the RPM quicker. Ultimately generating more HP. As long as the oil pump pickup stays submerged and avoids cavitation, you can run as little oil as possible. Not recommended for a street application. The next step is a dry sump system. Again, not for street use. Nick's brother built that 440 for strictly racing, and they are good at what they do.
