I just went and looked at my square blower housing model 6 and it has the air vane governor and had a recoil starter at one time, but now has a rope cup starter mounted on it. Still has the recoil starter holes in the blower housing. I prefer the square blower housing look over the older style.
Great looking engine.
RE: previous post about it possibly being a Model N - Could be. I have a Model N with a mechanical governor, but it has taller fins on the head ( I think...) and that cover would not fit like it does on the engine pictures above.
I was always under the impression that the air cleaner snorkel on your engine was a David Bradley exclusive. Do you know what your engine came off of?