machine shop?

True. But some jobs can only be done “so” fast. I’m not sure 350k would do a full shop.

A solid mill with the right fixtures will do a valve job and surface as fast as anything else. And you can use it for jobs a seat and guide machine and surfacer can’t do.
IDK much about milling machines but my google foo is pretty good.
https://seattle.craigslist.org/sno/tls/d/monroe-1999-bridgeport-mill-with-extras/7249954842.html
https://eastidaho.craigslist.org/bfs/d/shelley-bridgeport-r2e4-vertical-cnc/7241555178.html