It's likely been posted here before, but it's amazing to watch the ramming up and casting of a Wright Cyclone aluminium cylinder head at the 3:41 minute mark. From the film narration the mould and the core is baked in an oven for seven hours so I'm assuming it might be linseed oil bound sand, they do mention the sand is mixed with oil too. The narrow fin spacing has the guy who rams the mould throwing sand at the pattern to get it into the fins and then reinforcing with short wire pins.
We have a B25 at a nearby airfield. I have heard it start a a couple times and been in its hangar which is part of a museum. Those engines are impressive indeed. https://www.cafmn.org/north-american-b-25j.html
I work at the airport that's also home to the Canadian Warplane Heritage Museum, they have a large collection of flight worthy warplanes, many of them of WW2 vintage including at least couple use the Wright Cyclone R so I hear these engines on somewhat a regular basis.
My local airline: "Bush Pilots" operated a fleet of DC-3 up until 1988 and the sound of a Wright Cyclone or Wasp engine was part of the background noise as a kid. My Dad would send me down to their hangar to run errands and you'd see them x-raying some part of the plane as the planes approached 50 years old.
I visited that museum in April 2012. Well worth the visit and if you are in the Hamilton Ontario area make an effort to see it.
