Stovebold,
I think the problem lies in the fact that these are truly 'specialty' items. They come from contracted foundries and small time suppliers.
These folks have no true quality control department, and probably pay low wages with quick employee turnover.
I would classify the Stovebolt speed equipment manufacturers as almost a cottage industry.
This isn't an excuse for not having the hole in the proper place, or making the header flange flat, but keep in mind, this isn't BMW or General Electric.
I am a tinkerer, so I am not devastated when I have to use my die grinder to oblong a hole that isn't right.
Most American quality went overseas, lots is still around, but maybe lacking in the 'niche' speed equipment market.
Stuart