there are numerous ways to build a fuel system, the easiest way is to buy a tank with pump in it, then route the lines via the correct filter /regulator assy to either the hard line, soft line or soft line up to factory flex line.
While this is not the cheapest way, it does get you powder coated tank, fuel baffles and the correct factory style pusher pump with correct pressure. Lots of guys have just strapped pump on frame rail but you get what you pay for.
we have fuel line kits for all the different systems as well as the tanks. Our line kits are all USA made and around $150...you wont find a better deal on line kits. We also sell Tanks Inc tanks with pump, sender, straps for about $500 if thats in your budget. Cheaper than Scummit.
Otherwise, you will have to piece together stuff from here and there or pay closer to $250 for line kit usually with wrong regulator for magnum(LS vette regulator is wrong pressure for magnum). pm for info or look us up at magnummopar...