Hi
Bob, I have found most of the part numbers all the fittings and lines are Weatherhead/Eaton dug out the part numbers, the flex lines are Eaton 81430-16 and 81430-12 last two digits are the length so you can get the exact length after all the other fittings and lines are in place. NAPA number is WH 8143016 and WH813012 again last two digits are the length.
Is this the inverted flare fitting
you are talking about if so it is WH6100x4.
What I think we should try and do is get a good detail photo of the entire filter assembly, lines, fittings and try and plug in all the current part numbers or at least combinations of modern part that work. Here is a start.
The special head bolts on my truck seem to actually have been standard head bolts with another bolt welded to the head.
Cheers Phil