Every induction system, be it carbed or EFI, needs some way to get fuel. Fortunately, we were able to reuse the factory feed line since our Vortec 350 (see "Budget Sledgehammer," December 2006) topped out at 447 on the DTS engine dyno. You won't need to plumb a return line unless you're making over 550 hp. Professional Products makes a return fuel line kit (PN 70106, $324.50) which has 25 feet of -6AN braided line, a selection of 24 AN fittings, a regulator, and prefilter. Most people use it as a feed line, and convert the factory feed line to a return line.