Home enthusiasts discuss their Foundry & Casting work.
If you are so inclined to invest in some sand and binder and core paste you could ram the mold and make the cores. You could paste the entire assembly together leaving only the cope to be closed. Take it to the iron foundry and simply ask them to cut the gates and risers and close the mold and pour it. Most foundry so are more than willing to simply pour the mold and charge for metal and minimal labor. Of course you need to take whatever they pour. If you are not willing to accept whatever they pour then it may be best to fabricate your parts.
Back in the 1800's there were many small foundries, and they figured out how to do decent quality work, as much by trial and error as anything. Combine the foundry with a machine shop and they had full manufacturing capability for most any kind of machine they might be interested in. It surely can't be too hard to do with coke or charcoal and a cupola. I'm ready to fool with it myself but it's waiting on time away from other stuff. Too busy. I guess I'm interested in too many things and can't get em all in. But still. The main two interests are agriculture and metal working, making my own machines to use in small scale agriculture support work.