This is kind of old news, but see caveats below:
In late 2002 I bought into an engine program, and one of the machines that project bought was Z-corp machine which could (and still can) make casting flasks with a technology called z-cast. I have that machine in my possession now, but it's not hooked up and there'd be work to do to get it going. In any case, it was used to make flasks for pouring things like oil pumps. That process was one of the few things in that project that worked well.
Z-cast doesn't work for ferrous materials - really kind of restricted to aluminum, brass, etc.
The prometal process appears to go to at least cast iron.
In all of these processes, it's worth noting that they only make sense for short runs or super intricate stuff. (race engines are very small volume and change lots) If you want to make large volumes you'll make some kind of hard tooling.
Also, there's a process in which styrofoam is used as the pattern for a kind of "investment" casting - no draw, etc. required (as for 3D printed) I would assume the sytrofoam patterns are 3D printed at least some of the time. Can't saw how that compares with ProMetal.
