I see some of the vendors sell brake lines by the piece. Is there once source for a full set in stainless steel, I see this vendor has some, any others. Fuel lines in stainless also?
https://www.inlinetube.com/pages/product-list?year=7734226032956336614&make=1828299879717471912&model=3218048909376888140#?p=1
NPD is where I bought all of mine in SS preformed and fit so-so. You may need to tweak them here and there. Brake lines are harder to seal in SS, but doable. For the amount of driving most of us do in these classics, good quality ordinary steel lines will outlast the car, so your choice.
For fuel lines yes definitely I'd go SS. Again, I got mine from NPD. Again, it needed a bit of tweaking at the tank end. There are rubber pieces needed as well, buy Fuel Injector hose as it is ethanol resistant on the inside. Also PLEASE DO NOT USE gear clamps anywhere on fuel lines (or anywhere else for that matter!!) Make sure you use the correct clamps for the application. There are rubber grommets that go through the aprons, and shock towers, replace these at the same time. NPD sell these too.
If you replace your tank as well, I suggest the Spectra Premium tank from RockAuto (best price) and the Dorman 692232 sending unit. The Spectra one is wrong for our cars!!
Here are a couple of pics of my fuel lines.
This is what your old line might look like inside. This one had all but rusted through in places and caused filter blockage.
This end needed tweaking to line up with the tank connection. I added the rubber sleeve to stop vibration. Note the fuel line spring clamp.
As I have a Holley 4V carb, I made up a neater fuel line from pump to carb in 3/8" reg fuel line tube.
Poor picture, but shows my connection to the pump. The short piece of rubber acts as a vibration insulator and an easier connector.
I use a steel inline filter between the apron and pump, but idealy it ought to be after the pump, but space is too tight. Do NOT ever use glass filters!