My difficulty in understanding is that nearly 20 years have whizzed by since I last had a Regina 940 to work on occasionally for my late MIL. I remember and documented the lines at the tank, but don't recall anything about what the configuration was at the filter location. I assume the feed of fuel from the filter to the rail was just as it is in a 240 or Bosch-fueled car, with 5/16" OD nylon, but how the feed arrived at the filter input from the steel tube at the tank I have no recollection. Sounds like those are the fittings you're missing.

I'd suggest the parts drawings available from Volvo dealership websites, but those are confusing enough to us when we have the pieces in front of us much less trying to interpret the artist-conception illustrations.

Has to be someone still reading this site who has changed a fuel filter on a Bendix-fueled 7/9.
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Art Benstein near Baltimore

Eat, drink, and be thoughtful.