they contract out bids for everything and only assemble it. I've heard time and time again that if you can find out what your engine really is (i.e. who really made the block) that NAPA stores generally can find parts from the real maker, or other sources.
I permanently lost all chance of respect for Westerbleak once I head from a rep that they knew painting the rubber parts was wrong--but they did it anyway, because it was easier [read: cheaper] to assemble the entire engine, then paint it all as a finished product. Accountants!
You know why accountants use those #2 pencils with the rubber eraser on top? Because the actuaries told them that way there's only a 50% chance they can be stabbed to death with their own pencils.