High end parts are expensive no matter what brand of engine you run. As Monte said, a crank from Bryant is going to cost the same no matter what it's going in, etc etc. Shelf stuff is a different story, but records aren't set with running off the shelf parts. When you actually start spending the $$$ yourself on this level of engine, you'll understand where Monte and others are coming from.

I would also like to second what AndyF said, I do a similar thing on a much smaller scale. I know that I would never feed my wife and kids on making and selling Mopar parts. I make it as a hobby to please myself, and any parts I sell are usually to fund parts for the next project or my own race car. I am planning on doing some billet intake manifolds and billet heads in the next twelve months. If I can bank roll it, I will do a billet block while I am at it. I am fortunate enough to work in a fairly well equipped workshop from 9-5, for a boss who gives me time to entertain myself after hours.