Unfortunately, no smoking gun in the Hot Rod Magazine that had three engines sporting the valve cover, but- there are inklings it was a Bill Stroppe manufactured unit.
This makes sense as Bill Stroppe and associates are the ones souping the three 144 falcon engines for the article. A tri-power, a Paxton supercharged, and a Hilborn injected unit. For the injected unit, Stu Hilborn took a patterns for one of his foreign engines, cast and machined a new casting to fit the shaved and brazed head.