Fuel and brake line through frame?

You will never be able to service them. You will never be able to inspect them. I don't see any good way to fasten them to prevent rattles and rubbing. Chrysler did do this exact thing on some mid 60's C-body cars. I know this because when fuel started pouring out of a frame rail you take a good hard look at line routing. The replacement line was ran on the outside of the rails and the original was left inside cause there wasn't any way to remove it.