Mike, the 'info kits' aren't speculation or marketing, they're information from the manuals of the years collated by the historical dept, pretty much the final say on factory documentation
Bill
Bill,
I been thinking about your quote and looking over my 63 chevy shop manual. I am not convinced that the manual info should be the last say. These manuals were put together for general repair, not as all inclusive documentation. The 63 shop manual was intended for use through 66 with supplements each year. The book is large as it is, I could see why they might not include all info about 4x4 trucks. For the few who needed it, they could access the previous years manuals.
Also, the '4-wheel drive, section 14' of my 63 manual list the k series engine as a Thriftmaster witch is a 235? This seems to contradict the 'general info 0-5' section that list it as a 230.
I love a good mystery!