I wanted cast iron liners for both the cylinders and the valves.  I found cast iron sleeves made for a Studebaker that worked perfect for the piston cylinders.  The valve cylinder sleeves were made out of solid cast iron.  After I made the liners to rough size, I drilled 80 holes in them for the steam passages.  Then I had the honor of filing each one square.  If anyone attempts this, I suggest you get a new high quality file.  The one I used was 1/4" wide with smooth sides (Pillar?).  The pictures show one liner with drilled holes and the other filed square. 

I then pressed them into the cylinders and finished machining the ends and the final bore.  Here are the cylinders after 96 holes were drilled and tapped.  Studs will be installed after all machining is done.