Sometimes the issue with
oil usage can be related to mis-manufactured parts and not mechanic issues. I and previous owners were chasing down
oil usage issues on my FE that came down to a poorly manufactured intake manifold that was not square. When the intake manifold was replaced with a new one that was properly manufactured (same manufacturer for both) the
oil consumption issue disappeared. It can be difficult to mix engine parts from different suppliers too.
I think that one issue that may not get adequately addressed here is the understanding that when you start to push horsepower into the 600+ range engine longevity suffers. Most racers rebuild their engines after a season of racing because the engines need it; excessive wear is common and internal parts receive a lot of abuse with that degree of power. For most of these engines we are talking about a season being typically less than 500 miles worth of use. In many instances less than 250 miles. I know of people who build high horsepower engines for their race cars with the understanding that the engine will be good for one race.