A couple of comments on cammers and the early factory efforts.
The earliest sparkplug location, down low on the rocker/cam covers, was where the design started. The plugs were located in the theoretical 'ideal' place for such things as flame propagation/flame front travel. Frustration was quickly evident because these earliest heads didn't produce much more power than the high-riser design they were intended to supersede.
A variety of fixes were attempted---among them moving the plugs so that they were in a less advantageous-seeming location in the combustion chamber but one that had the benefits of making it much easier to r-'n'-r the plugs and also,with that one change, magically 'found' an extra hundred or so horsepower. There were other detail changes, including, ultimately, a material change from iron to aluminum for the head castings.
Now you know the rest of the story. (I had a kit, consisting of the early low sparkplug heads and the covers and a bunch of other stuff.) I was lucky to know someone who knew someone, and was gifted with a set after they were thrown to one side at some place in the bowels of Triple E, The stuff wasn't good for anything but interesting garage wall hangings. I still have a set of lash caps here in one desk drawer. I'n mot sure, this long thereafter, if they're from that long-ago bunch of stuff---I gave the bulk of it away before an impending move more than 40 years ago---or a set I sourced from Carl Holbrook's 'stash', used to give a better geometric lay-out for an engine I built with Dove castings.
KS