old fuel lines and brake lines -Replacement Where and How? Tech tips please!

I used this 3/8" copper/nickle line for my fuel line. Super easy to bend and make straight. If you do some searches theres lots of good info on this type of material, and its been around for years. Copper Nickel Brake Fuel Line Tubing Kit 3/8 OD 25 Ft Coil Roll INLINE TUBE CN6 | eBay