Are you making your own lines or buying pre-made?
You can usually get standard 3/16 lines in 8" - 5' lengths, and fitting the long line down inside the frame rail beside the gas tank can be challenging.
I make all my own lines from nickel/copper with a double flare tool.
In any case the nicopp tube is a
LOT easier to work with.
If you're replacing the drivers side rear axle wheel cylinder line be aware that the fitting at the brass junction block is an odd oversized nut.
So, if you're using off the shelf 3/16 tube you need the (unobtainable) adapter ifitaintbroke mentioned above.
If you're making your own lines you can reuse the nut, if it isn't completely destroyed.
Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.