sharpe
You raise a very good point about visiting a foundry. I would be very interested in learning more about the casting process. I am sure that it is very interesting. Up here we call them frost plugs but many of my American friends call them freeze plugs. Interesting to know that they are actually core plugs. By the way, they do pop out when water freezes in the block but the block usually cracks anyway, most of the time just about a half inch or so above the
oil pan gasket.