5851a, as you surmised, it was a typo, I corrected it.
KULUTZ, I'm sure you must then, be unaware that Ford releases cars to magazines, for advertising and promotional purposes. In doing so, they also supply information that they want to be publicly known but, beyond that my purpose for including that HR reference, was to prove a time line i.e. you can't do a article on something that doesn't exist.
If a new model is offered for promotion, from the factory, with non RPO equipment, it would likely be a sign, that it's a prototype and that is a way to date something.
The HR article was the first reference of the 360HP, if the 360HP was produced in Sept, because it was a big deal, it would have been promoted somewhere between Aug and Oct of '59 and not Dec & Jan (MT).
Lastly, I'm not like you, I document my info and include any thing that that I've heard, from what I consider a reliable source.
You ask me for pictures and documentation and I provide it! I ask the same of you and you provide, only excuses of why you can't or won't!
It may be foolish on my part but, again, I'll ask you for documentation of your statement that a outside source cast the intakes.