The 12 Port Head design was first on the drawing board in 1939. As panic pointed out, there were other better combustion chamber designs already being used by other manufacturers, but whether Wayne or Horning actually realized those other designs were better, they for some reason created the 12 Port head in the open chamber style design. If a modern approach was put on that head today, it would likely be capable of much higher power levels similar to a Sissell or Duggan 12 Port head.
