Gold? no they are made of iron and I have been hard pressed to get any one to spend $400 for one that already has machine work done to it that would need to be done to it anyway. I don't have any plans to use them but im not going to scrap them but I think 400 is a fair price for a cleaned and rough bored block. No not sonic checked but to each his own, just don't say they are hard to find. They are not...