Okay... It appears that I missed a LOT of things.
The head in most of the pictures is clearly a "775" casting, unless the PDF is distorting the image, which I doubt.
The parts list shows a "776" part number, but it is shown as discontinued, as of that publication. (Actually, '83.)
In any event, it appears that they are discussing either my head, or one that is very similar. (Obviously not the high port head, but that's okay with me.)
Thanks very much.
I wonder if the high port and/or aluminum heads are that much improved over this casting. Everything I have seen on the web discusses the later aluminum heads.
Either way... much appreciated.