Since you know and according to the SSDI, Julia died in Sept. 1970, it might be very beneficial for you to send for her Social Security Application. Furnish as much information as you can on the form, which is printable from the computer. Like the civil marriage record, this is one of the very few documents available that the person his/herself provided the information for. It is likely she gave her maiden name as it was and at least you would get the correct spelling. With some good fortune, you may get a town in Norway and, if so, you could try going further back via such information if that is your goal.
The Mormon website doesn't provide anything for Norway under Graw/Grow but does have some names under Grav so that is a Norwegian name.
If you're looking for a manifest, don't over-do it with giving information to the website...less is more...and play with spellings. Even if Grav is the name, consider that the transcriber may have seen it as Grov, Grev, Crov, etc. Maybe "only" enter a last name. Have you seen Steve Morse's site? It's quite helpful.