Well, i'm no expert on this, since every V8 conversion i've been a part of ended up as a carbed version, which really changes the fuel system a lot. My guess is that you want to find a donar V8 car and just swap over the entire fuel system, gas tank and pumps included. If Ford thought the 4 cylinder fuel system would be up to par for the V8 then there wouldnt be a difference between the two. As for finding them new, check 5.0 Resto or even a Ford dealership, you might get lucky with Autozone or Advanced but i'd go with OEM if you can't afford braided lines.